Answer:
All of the above
Explanation:
Scientific theories are explanations of various well known facts. They are hypotheses that best explain a scientific phenomenon. More development of theories doesn’t make it acceptable.
Instead they have to supported by the results of several tests performed by employing proper scientific methods. It is only after several years of thorough scientific research a theory is accepted as the best explanation of a phenomenon. Unlike facts that are accepted as universal truths theories can be proven wrong over time .
Answer:
all of the above
Explanation:
In the periodic table of elements, what do all of the elements in group 2 have in common?
Answer:
The correct answer is chemical properties.
Explanation:
In a group, the chemical properties are very similar, because all the elements of the group have the same number of electrons in their last or last layers. The electronic configuration of its last layer is the same, varying only the period of the element. Alkaline earth metals are harder than alkaline metals, have brightness and are good electrical conductors; less reactive than alkalines, good reducing agents and form ionic compounds.
Have a nice day!
wavelength if the wave
Answer:
A what? Is this even a question?
Explanation:
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Answer:
Velocity is a change in displacement over change in time and uses the units m/s.
Both are rates of change and can be positive or negative.
Acceleration is a change in velocity over change in time and uses the units m/s².
Explanation:
Velocity is the change in displacement over change in time, this makes it a rate of change. It can be positive or negative because it is a vector quantity. It uses the units m/s because that is a displacement unit over a time unit.
Acceleration is the change in velocity over change in time, this makes it a rate of change. It can be positive or negative because it is also a vector quantity. It uses the units m/s² (m/s/s) because that is a velocity unit over a time unit.
A sailor pulls a 2,000 kilogram boat 25 meters along the dock with a rope attached to the boat that makes a 45 degree angle with the dock. How much work is done by the sailor if he exerts a force of 400 newtons while pulling the boat?
Answer: 7071.067 Joules
Explanation:
The Work [tex]W[/tex] done by a Force [tex]F[/tex] refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path [tex]d[/tex].
It should be noted that it is a scalar, and its unit in the International System of Units is the Joule (like energy). Therefore, 1 Joule is the work done by a force of 1 Newton when moving an object, in the direction of the force, along 1 meter:
[tex]1J=(1N)(1m)=Nm[/tex]
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:
[tex]W=(F)(d)[/tex] (1)
When they are not parallel, both directions form an angle, let's call it [tex]\alpha[/tex]. In that case the expression to calculate the Work is:
[tex]W=Fdcos{\alpha}[/tex] (2)
In this case the force and the distance in the path form an angle [tex]\alpha=45\°[/tex], so we will use the second equation, where [tex]F=400N[/tex] and [tex]d=25 m[/tex]:
[tex]W=(400 N)(25 m) cos(45\°)[/tex] (3)
Then:
[tex]W=7071.067 Nm=7071.067 J[/tex]
The work done by the sailor to pull the boat 25 meters with a force of 400 newtons at a 45-degree angle to the dock is approximately 7,071 Joules.
The amount of work done by the sailor on the boat can be calculated by using the formula for work done by a force at an angle, which is W = F imes d imes ext{cos}( heta). In this case, the force (F) is 400 newtons, the distance (d) is 25 meters, and the angle ( heta) is 45 degrees.
First, we calculate the cosine of the angle, which in this case is ext{cos}(45^{ ext{o}}) = rac{ ext{ extsqrt{2}}}{2}.
Then, we multiply the force, distance, and cosine of the angle: W = 400 N imes 25 m imes rac{ ext{ extsqrt{2}}}{2}.
Therefore, the work done by the sailor is 400 imes 25 imes rac{ ext{ extsqrt{2}}}{2}, which equals 7,071 Joules approximately.
How are energy of motion and speed are related to each other?
The energy transferred is known as kinetic energy, and it depends on the mass and speed achieved. Kinetic energy can be transferred between objects and transformed into other kinds of energy.
Which of the following do you calculate
when you divide the total distance trav-
eled by the total travel time?
significant digits show the _____ of measurements and calculations.
1) accuracy
2) precision
A right triangle with the base labeled 40 meters and the height labeled 30 meters. The hypotenuse is a dotted arrow labeled R. What is the magnitude of the resultant vector? 10 meters 50 meters 1200 meters 2500 meters
Answer:
The magnitude of the resultant vector R is 50 meters ⇒ 2nd answer
Explanation:
The resultant vector is the vector sum of two or more vectors
If the two vectors perpendicular to each other, then the magnitude of
the resultant vector is the square root of the sum of their squares
If x and y are two vectors perpendicular to each other, then the
magnitude of its resultant vector R is:
→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]
Lets solve the problem
A right triangle with the base labeled 40 meters and the height labeled
30 meters
The hypotenuse is a dotted arrow labeled R
→ The base and the height of the right triangle are perpendicular
→ The hypotenuse is the resultant vector of them
Assume that x represents the base of the triangle and y represents the
height of it
By using the rule above
→ x = 40 m , y = 30 m
→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]
→ [tex]R=\sqrt{(40)^{2}+(30)^{2}}[/tex]
→ [tex]R=\sqrt{1600+900}[/tex]
→ [tex]R=\sqrt{2500}=50[/tex]
The magnitude of the resultant vector R is 50 meters
What will happen to an object at rest if no unbalanced forces act on it,
according to Newton's First Law?
Explanation:
Newton's first law says that an object at rest stays at rest, and an object in motion stays in motion, until acted upon by an unbalanced force.
If there's no unbalanced force, then an object at rest will stay at rest.
What is gas pressure
Answer:
Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.xplanation:
Answer:
Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.
Explanation:
Bernoulli’s principle states that fluid velocity decreases when flow is restricted. True False
Gravitational pull is determined by
-the sun and stars
-acceleration and volume
-volume and mass
-mass and distance
Answer:
The gravitational pull is determined by the mass and distance.
Explanation:
According to Newton's law of universal gravitation
[tex]F = G\frac{m1.m2}{r^{2} }[/tex]
where F is the gravitational pull, G is gravitational constant, m₁ and m₂ are masses of bodies and r is the distance between them.
It can be seen from the above equation that F is directly proportional to the product of the masses and inversely proportional to the square of distance between them.
F ∝ m₁m₂
F ∝ 1/r²
A car is traveling at 10m/s before it increases its speed to 30m/s for 120m. How long does it take to do this ?
Answer:
60 seconds
Explanation:
Given:
v₀ = 10 m/s
v = 30 m/s
Δx = 120 m
Find: t
Δx = ½ (v + v₀)t
120 = ½ (30 + 10) t
t = 60
It takes 60 seconds.
How are light and sound waves affected by the different media they travel though?
Final answer:
Sound waves, as mechanical waves, need a medium to travel and are affected by its properties, while light waves, which are electromagnetic, can travel through a vacuum. When light travels through media of different densities, it experiences changes in speed, leading to refraction and reflection, changing brightness and color perception.
Explanation:
Light and sound waves are fundamentally different in how they interact with various media they travel through. Sound waves are mechanical waves meaning they require a medium like air, liquid, or solid to travel. The density and elasticity of these media affect the speed and quality of sound, with denser media generally allowing faster sound transmission. Also, movements in the medium, such as wind, can also influence the speed and direction of sound waves.
On the other hand, light waves, being electromagnetic waves, do not require a medium and can travel through a vacuum. However, when they pass through different media, their speed can vary. In denser media, light waves slow down which can lead to phenomena such as refraction (bending of the light) or reflection. The changes in speed and direction make light interact with objects differently, often affecting the brightness and color as perceived by the observer.
A bulldozer does 4,500 J of work to push a mound of soil to the top of a ramp that is 15 m high. The ramp is at an
angle of 35° to the ground. How much force did the bulldozer apply to the mound of soil? Round your answer to two
significant figures.
Its 520 N
Answer:
520 N
Explanation:
Work is the dot product of the force vector and displacement vector.
W = F · x
This means it is the product of the magnitudes of the vectors and the cosine of the angle between them.
W = F x cos θ
The displacement of the soil is 15 m up. The force is parallel to the ramp. So the angle between the vectors is 90° − 35° = 55°.
Plugging in the values and solving for F:
4500 J = F (15 m) (cos 55°)
F = 523 N
Rounded to two significant figures, the force is 520 N.
An object is thrown directly up (positive direction) with a velocity (vo) of 20.0 m/s and do= 0. How high does it rise (v = 0 cm/s at top of rise). Remember, acceleration is -9.80 m/s2.
d = _____ m
1.02
2.04
20.4
40.8
Answer:
20.4
Explanation:
Given:
y₀ = 0 m
v₀ = 20.0 m/s
v = 0 m/s
a = -9.80 m/s²
Find: y
v² = v₀² + 2a (y − y₀)
(0 m/s)² = (20.0 m/s)² + 2 (-9.80 m/s²) (y − 0 m)
y = 20.4 m
How are the input and output forces of the parts of a compound machine related?
Answer:
Within a compound machine, the output force of one simple machine becomes the input force of another simple machine.
pls how to solve this problem. help would be appreciated
Answer:
80 m/s
Explanation:
Given:
a = -5 m/s²
v = 0 m/s
Δx = 640 m
Find: v₀
v² = v₀² + 2a(x − x₀)
(0 m/s)² = v₀² + 2(-5 m/s²) (640 m)
v₀ = 80 m/s
3. A car drives horizontally off of a cliff that is 40 meters tall and lands 65 meters from the base of
the cliff. What was the initial velocity of the car?
Answer:
23 m/s
Explanation:
First, find the time it takes for the car to fall 40 meters.
y = y₀ + v₀ t + ½ at²
0 = 40 + (0) t + ½ (-9.8) t²
0 = 40 − 4.9 t²
t = 2.89 s
Next, find the velocity needed to travel 65 meters in that time.
x = x₀ + v₀ t + ½ at²
65 = 0 + v₀ (2.89) + ½ (0) (2.89)²
v₀ = 22.75 m/s
Rounding to two significant figures, the car's initial speed was 23 m/s.
I give a ball a push on an acclivity. The "start velocity" is on 7m/s. The time it took the ball to get back to me was 10 seconds. The acceleration is a constant. How much is the acceleration?
Answer:
7÷10
Explanation:
initial velocity=7m/s
final velocity=0m/s
Answer:
-1.4 m/s²
Explanation:
The initial velocity is 7 m/s. When the ball rolls back, its velocity is -7 m/s.
Acceleration is change in velocity over change in time.
a = Δv / Δt
a = (-7 m/s − 7 m/s) / 10 s
a = -1.4 m/s²
Anna heated 15 g of Substance A to obtain 5 g of Substance B, 4 g of Substance C, and a certain amount of Substance D. Which statement is correct?
The mass of Substance D was 10 g less than the mass of Substance A.
The mass of Substance D was 1 g greater than the mass of Substance B.
The mass of Substance A was equal to the total mass of Substance C and Substance D.
The mass of Substance A was equal to the total mass of Substance B and Substance D.
Answer:
The mass of Substance D was 1 g greater than the mass of Substance B.
Explanation:
15 g of A → 5 g of B + 4 g of C + x g of D
From the law of conservation of mass, Mass of D should be x = (15 - 5 - 4 ) g = 6 g
This is 1 g more than the mass of B and 2 g more than mass of C.
Thus, correct option is The mass of Substance D was 1 g greater than the mass of Substance B.
how much force would be needed to move a car with the mass of 100kg to an acceleration of 5m/s/s?
Answer:
500 newton force is needed to move a car of mass 100kg to an acceleration of 5m/s/s.
Explanation:
As we know from Newton's second law of motion that force= F = m×a
=> F = 100 × 5 = 500 N
Kepler's third law relates the period of a planet
to its orbital radius r, the constant G in Newton's law of gravi-
tation (F = Gm1m2/r^2), and the mass of the sun M.. What com-
bination of these factors gives the correct dimensions for the
period of a planet?
Answer:
√(r³ / (MG))
Explanation:
The dimensions of each variable are:
r = [m]
G = [m³/kg/s²]
M = [kg]
Multiplying M and G eliminates kilograms:
MG = [m³/s²]
The radius cubed divided by MG eliminates meters:
r³ / (MG) = [s²]
The square root gives us seconds:
√(r³ / (MG)) = [s]
Kepler's third law relates the time period of a planet to its orbital radius r, the gravitational constant G and the mass of the sun M, the combination of these factors gives the correct dimensions for the period of a planet would be √( 4πr³/GM)
What are Kepler's laws of planetary motion?There are three laws of Kepler as follows
The orbit of the planet is elliptical and the sun is present at one of the two focuses of the elliptical path followed by the revolving planet.
A line segment joining a planet and the Sun covers equal areas during equal intervals of the time period.
The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its elliptical orbit.
Think about a small mass M traveling in a circle around a large mass M. The centripetal force for mass m comes from gravity. Taking circular motion as an example and applying Newton's second law,
gravitational force balances the centripetal force
GMm/r² = mv²/r
GM/r = v²/r
Let us take a Time period of the orbital is P
v = 2πr/P
GM/r = 4πr²/P²
P² = 4πr³/GM
P = √( 4πr³/GM)
Thus the correct dimension for the time period in terms of the orbital radius (r), gravitational constant (G ), and the mass of the sun (M) would be √( 4πr³/GM).
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An astronaut on spacewalk floats a little to far from space station without air to push against he can’t paddle back however he is holding a hammer explain how he could use the hammer to get him back to space station l
Answer:
The astronaut can throw the hammer in a direction away from the space station. While he is holding the hammer, the total momentum of the astronaut and hammer is 0 kg • m/s. According to the law of conservation of momentum, the total momentum after he throws the hammer must still be 0 kg • m/s. In order for momentum to be conserved, the astronaut will have to move in the opposite direction of the hammer, which will be toward the space station.
Explanation:found this as a verified answer on here
Answer:
He can throw the hammer in the direction opposite to the direction he wants to travel in. The hammer will exert an equal and opposite force on him, as per Newton's third law, and this will help him move towards the space station
Explane
above
which system of government has a leader that takes power by force
Answer:
The Autocratic system of governance
Explanation:
This is because,in Autocratic system of governance decision making is done by only individual. And his/her decision is final.
Answer:
The Autocratic system of governance
Explanation:
At summer camp, the swimming course runs the length (L) of a small lake. To determine the length of the course, the camp counselors measure the two "dry" legs of a right triangle. What is the length in meters of the swimming course in the figure below? A right triangle overlaps a lake. It has sides 25 and 40 meters. Hypotenuse labeled L goes through the lake.
Answer:
The length of the swimming course is 47.16 meters.
Explanation:
It is given that the right triangle overlaps the lake and hypotenuse L runs through the length of the lake. Thus length of the lake will be the length of this hypotenuse.
The instructors have conducted measurements of the right triangle and has found the legs to be 25 and 40 meters. The sum of squares of base and height of a right triangle gives the value of its hypotenuse according to Pythagoras theorem.
Thus [tex]h^2+b^2=H^2[/tex]
b - base
h - height.
[tex]40^2+25^2=1600+625=2225[/tex]
[tex]H=\sqrt{2225}=47.16 m[/tex]
Which of the following is a way that microwaves and x-rays are similar?
A. They both have technological uses.
B. They are both high energy waves,
C. They are both to be exposed to at high doses.
D. They are both used to transmit information.
(I’m between A and B)
Answer:
A
Explanation:
In my opinion I'm pretty sure it's A because WE DO use microwaves and x-rays as techonological uses.
Answer:
A
Explanation:
a granite monument has a volume of 25,365.4 cm3. The density of granite is 2.7 g/cm3. Use this information to calculate the mass of the monument to the nearest tenth.
The mass of the granite monument is
g.
Answer:
The mass of the monument (to the nearest tenth) where volume of the granite monuments is [tex]25,365.4 \mathrm{cm}^{3}[/tex] and density of the granite is [tex]2.7 g / \mathrm{cm}^{3}[/tex] is 68,486.6 g
Explanation:
Given:
Volume of the granite monument, p[tex]=25,365.4 \mathrm{cm}^{3}[/tex]
density of granite, [tex]V=2.7 \mathrm{g} / \mathrm{cm} 3[/tex]
To find:
The mass of the monument to the nearest tenth= ?
Solution:
Step 1:
mass of the monument ,[tex]m=p V \text { grams }[/tex]
step 2:
[tex]m=p V[/tex]
substituting the values,
m[tex]=(25,365.4)(2.7)[/tex]
m[tex] =68,486.58 g[/tex]
m [tex]= 68,486.6 g[/tex] (rounding off to nearest tenth)
Result :
The mass of the monument (to the nearest tenth) where volume of the granite monuments is [tex]25,365.4 \mathrm{cm}^{3}[/tex] and density of the granite is [tex]2.7 \mathrm{g} / \mathrm{cm}^{3}[/tex] is 68,486.6 g.
The mass of the granite monument is 68,486.58 g which has a volume of [tex]25364.4 cm^{3}[/tex] and density of [tex]2.7 gcm^{-3}[/tex].
Given data:
To calculate the mass of the granite monument, we can use the formula:
mass = density * volume
Given that the density of granite is [tex]2.7g cm^{-3}[/tex] and the volume of the monument is [tex]25364.4 cm^{3}[/tex]
we can substitute these values into the formula:
mass = 2.7 * 25,365.4
Calculating the mass:
mass = 68,486.58 g
To express the mass in kilograms, we can divide by 1000 (since there are 1000 grams in a kilogram):
mass = 68,486.58 g / 1000 kg
Calculating the mass in kilograms:
mass = 68.48 kg
Hence, the mass of the granite monument is approximately 68.57 kg, rounded to the nearest tenth.
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what is the best description of a wave
A wave is a disturbance that travels through space and matter, characterized by its wavelength, frequency, and amplitude.
Explanation:A wave is a disturbance or oscillation that travels through space and matter, transferring energy from one place to another. Waves are characterized by three main features: wavelength, frequency, and amplitude. The wavelength is the distance between two identical points on successive waves. The frequency refers to the number of wave cycles that occur in a second. The amplitude is a measure of the wave's height from the rest position.
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A hockey puck slides across the ice with an initial velocity of 7.2 m/s. It has a deceleration of 1.1 m/s2 and is traveling toward the goal 5.0 m away. How much time does the goalie have to stop the puck
Answer:
0.74 s
Explanation:
We can solve the problem by using the following SUVAT equation:
[tex]d = ut + \frac{1}{2}at^2[/tex]
where
d = 5.0 m is the displacement
u = 7.2 m/s is the initial velocity
a = -1.1 m/s^2 is the acceleration (which is negative since it is a deceleration)
t is the time
Substituting numbers into the equation, we find:
[tex]5.0 = 7.2 t -0.55t^2\\0.55t^2 -7.2t + 5.0 = 0[/tex]
This is a second-order equation, whose solutions are given by:
[tex]t=\frac{-(-7.2) \pm \sqrt{(-7.2)^2-4(0.55)(5.0)}}{2(0.55)}[/tex]
And the solutions are
t = 0.74 s
t = 12.36 s
The solution we are looking for is the first one, because it corresponds to the first time at which the hockey puck has travelled the distance of 5.0 m, reaching the goal.
The goalie has approximately 6.55 seconds to stop the hockey puck. This is calculated using the motion equation v = u + at, taking into account that the puck is decelerating.
Explanation:This is a question of physics, specifically dealing with the concept of motion and deceleration. We use the equation of motion that relates final velocity (v), initial velocity (u), acceleration (a), and time (t): v = u + at. However, since the puck is decelerating, we are actually dealing with a negative acceleration.
Therefore, the equation becomes final velocity (0 m/s because it will eventually stop sliding) = initial velocity (7.2 m/s given) + acceleration (-1.1 m/s²) * time.
By rearranging this equation we can solve for time (t): t = (final velocity - initial velocity) / acceleration. So it then becomes t = (0 - 7.2) / -1.1. Solving this yields a time of approximately 6.55 seconds for the puck to stop.
Note: The distance to the goal does not play a role in the time it takes for the puck to stop sliding because the puck's motion is determined by its initial velocity and deceleration, not its destination.
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