A compact car with a mass of 1,000 kg, traveling at 15 m/s, runs into and sticks to - an at-rest SUV of 2,200 kg. What is the final speed of the two cars? A. 4.7 m/s B. 67 m/s C. 2.2 m/s D. 147 m/s

Answer:

Doppler effect refers to apparent change in frequency/wavelength of the source due to the relative motion between the source and the observer. The frequency increases apparently if the source and observer approach each other and it decreases apparently if the source and the observer move away from each other.

When, apparent frequency increases, it is known as blue-shift and if it decreases, it is known as red-shift.

Answer:

D. Less and less of the moon.

Explanation:

Waning has the meaning decreasing. A waning moon is the moon that decreases in size and its illumination . Moon starts waning a day after the full moon. Its size keeps decreasing and ultimately it is not visible on the new moon day .

A day after the new moon, it starts increasing in size and brightness and is slowly visible each night, until it is completely shining on the full moon day again. This is the waxing of the moon, where its size keeps increasing.

Answer:

Explained

Explanation:

A student who runs every day is becoming bored with her physical fitness routine and considers quitting. Now in order maintain her fitness routine she needs to break the monotony by changing her exercise regime. She do other activities like play sports two days a week, she do aerobics, she even try some cardio vascular exercises which as good as running. She also try changing her route of running as the new view might inspire her.

Answer:

The force needed is 400 Newtons.

Explanation:

The force can be determined by means of Newton's law.

[tex]F = m \cdot a[/tex]  (1)

Where F is the force needed to stop the football player, m is the mass of the football player and a is the acceleration.

[tex]F = (80 kg)\cdot (5m/s^{2})[/tex]            

[tex]F = 400 kg.m/s^{2}[/tex]

However, 1N = 1 kg.m/s^{2}

[tex]F = 400 N[/tex]

Hence, the force needed is 400 Newtons.        

Answer:

Length of one stadium = 0.1556 km

Explanation:

We have the diameter of Earth = 12740 km

Thus, circumference (C) of Earth is

[tex]=2\pi \frac{Diameter}{2} \\[/tex]

[tex]=2\times \pi \times \frac{12740}{2}[/tex]

C = 40023.89 km

Eratosthenes was a Greek polymath. He was the first to calculate the circumference of Earth. He had observed that at local noon on day of Summer Solstice, when Sun is overhead for the locations on Tropic of Cancer, a place named Syene had zero shadow day. Also on the same day the objects in Alexandria casts shadow. This proved that Earth is spherical and not flat. He went further and calculated the Sun angle ([tex]\theta[/tex]) for Alexandria by using a Rod (Gnomon). He found the angle to be about 7°. He also knew the distance (D) between Alexandria and Syene which was 5000 Stadia.

Lets say length of one stadia = S km

He used this data and simple concept of geometry as given below:

[tex]\frac{\theta }{360}=\frac{D}{C}[/tex]

[tex]=\frac{7}{360}=\frac{5000 \times S}{40023.89}[/tex]

[tex]=5000 \times S = \frac{7\times 40023.89}{360}[/tex]

[tex]=S = \frac{7\times 40023.89}{360\times5000}[/tex]

S = 0.1556 km

Final answer:

Water turns to steam by absorbing energy that increases the kinetic and potential energy of water molecules, allowing them to escape into the air as gas. So the correct option is C.

Explanation:

When water turns to steam, it absorbs energy which causes the water molecules to have more kinetic and potential energy, changing their configuration from a liquid to a gas. During the process of boiling, heat energy increases the water molecules' kinetic energy, leading to the breaking of hydrogen bonds that held water molecules close together. When these bonds break, water molecules can move freely and escape into the air as steam or water vapor. This endothermic transition requires a significant amount of energy due to water's high heat of vaporization.

The correct statement describing this change of state is thus:
C.The water absorbs energy which causes the water molecules to have more kinetic and potential energy, changing their configuration from a liquid to a gas.

Diffraction is sounds with a larger wavelength to bend around obstacles more easily. Therefore, option A is correct.

Diffraction is the interference or bending of waves via an aperture into the area that is geometrically in the shadow of the obstruction or aperture. Effectively, the wave's secondary source is the diffracting element or aperture.

The bending of waves with a larger wavelength around objects or through apertures with a shorter wavelength results in wave diffraction. If this condition is satisfied, diffraction can occur for both light and sound waves.

Wavelengths of visible light span from 380 to 700 nanometers. Light must pass through an opening that is smaller than 1,000 nanometers for diffraction to take place.

Thus, option A is correct.

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Diffraction refers to the bending of waves around obstacles or through small openings. In the case of sound waves, sounds with a larger wavelength bend around obstacles more easily. This is because sound waves have long wavelengths compared to the size of the obstacles.

Diffraction refers to the bending of waves around obstacles or through small openings. In the case of sound waves, the correct answer is option a. Sounds with a larger wavelength bend around obstacles more easily. This is because sound waves have long wavelengths compared to the size of the obstacles. On the other hand, light waves have very short wavelengths and behave more like rays, so they do not diffract around large obstacles.

C)Weight

A)An attraction between two objects that have mass

B)Force decreases as distance increases.

grav force of massive planet increases your weight

Answer:

C)Weight

A)An attraction between two objects that have mass

B)Force decreases as distance increases.

Explanation:

The total amount of energy absorbed by a substance as it changes from a solid to a gas at different temperatures can be calculated using the formula Q = m × ΔH. First, calculate the energy required to raise the temperature of the substance. Then, calculate the energy required for the phase changes. Finally, add all the energy values together to find the total amount of energy absorbed.

The total amount of energy absorbed by a substance as it completely changes from a solid to a gas can be calculated using the formula:

Q = m × ΔH

Where:
- Q is the total energy absorbed
- m is the mass of the substance
- ΔH is the enthalpy change of the substance

First, calculate the energy required to raise the temperature of the substance from 40°C to its melting point. Then, calculate the energy required to change the substance from a solid to a liquid. Next, calculate the energy required to raise the temperature of the substance from its melting point to its boiling point. Finally, calculate the energy required to change the substance from a liquid to a gas. Add all these energy values together to find the total amount of energy absorbed.

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With Earth's gravity being [tex]9.80 m/s^2[/tex] the mass is approximately 5.61 kg.

To calculate the mass of an object that weighs 55N on Earth, we need to use the formula for weight, which is w = mg, where w is weight, m is mass, and g is the acceleration due to gravity.

On Earth, g is typically [tex]9.80 m/s^2[/tex]

Therefore, we can find the mass of an object by dividing its weight by this acceleration due to gravity.

To calculate the mass (m) of an object that weighs 55N on Earth:

m = w / g

[tex]m = 55 N / 9.80 m/s^2[/tex]

This calculation results in a mass of approximately 5.61 kg.

Answer:

Explanation:

The uplift caused a wide range of elevations and climates in the Sierra Nevada, which are reflected by the presence of five life zones (areas with similar plant and animal communities).

Net force that is required to bring the car to a halt =6400 N

Explanation:

Using kinematic equation to calculate the acceleration a

Vf²= Vi²+ 2 a d

Vf= final velocity=0

Vi= initial velocity= 20 m/s

a= acceleration

d= distance=50 m

0²= (20)²+ 2 a (50)

a=-4 m/s²

Now force= F = ma

m= mass= 1600 kg

F= 1600 (-4)

F=-6400 N

negative sign indicates that the force is opposing the motion of the car.

The correct answer is C. Thermal conductivity

Explanation:

Conduction occurs as heat, electricity, etc. are transmitted from one body to another. In the case of thermal conductivity, this refers to the property of one material or body to transmit or conduct heat. This property is measured in Watts (energy) per meter(distance)-Kelvin (temperature). For example, the thermal conductivity of copper is around 385 while the one of ice is 1.6, which indicates copper has a higher capability to conduct heat. Thus, the degree to which a material can transmit heat is thermal conductivity.

Answer: The answer is C. Food.