Wave Motion Quiz

The time needed for a wave to make one complete cycle is its

• frequency.

• velocity.

• amplitude.

• period.

• wavelength.

Answer explanation

The time needed for a wave to complete one cycle is called its period. It is the inverse of frequency, which measures how many cycles occur in a given time. Thus, the correct answer is period.

The source of all wave motion is a

• region of variable high and low pressure.

• vibration.

• movement of matter.

• harmonic object.

Answer explanation

The source of all wave motion is a vibration, as it creates oscillations that propagate through a medium, leading to the formation of waves. Other options do not directly initiate wave motion.

Which letter in the graph above represents the amplitude?

• A

• B

• C

• D

Answer explanation

The amplitude of a wave is represented by the distance from the midline to the peak or trough. In the graph, letter C indicates this distance, making it the correct choice for representing amplitude.

Which letter in the graph above represents the wavelength?

• A

• B

• C

• D

Answer explanation

In the graph, the wavelength is represented by the distance between two consecutive peaks or troughs. Letter D marks this distance, making it the correct choice for representing the wavelength.

Which of the following is NOT an example of harmonic motion?

• A swinging pendulum

• A bouncing spring.

• A bouncing ball.

Answer explanation

A bouncing ball does not exhibit harmonic motion because its motion is not periodic and is influenced by gravity and energy loss, unlike a swinging pendulum or a bouncing spring, which both have regular, repeating patterns.

A mass attached to a spring vibrates back and forth. At maximum displacement, both the spring force and the

• velocity reach a maximum.

• velocity reach zero.

• acceleration reach a maximum.

• acceleration reach zero.

Answer explanation

At maximum displacement, the spring is fully stretched or compressed, resulting in the maximum spring force. However, the velocity is zero at this point, while the acceleration, due to the spring force, reaches a maximum.

If a force of 50 N stretches a spring 0.10 m, what is the spring constant?

• 5 N/m

• 500 N/m

• .1 N/m

• 5000 N/m

Answer explanation

The spring constant (k) can be calculated using Hooke's Law: F = kx. Rearranging gives k = F/x. Substituting F = 50 N and x = 0.10 m, we get k = 50 N / 0.10 m = 500 N/m. Thus, the correct answer is 500 N/m.

How much displacement will a coil spring with a spring constant of 120 N/m achieve if it is stretched by a 60 N force?

• 0.5 m

• 2 m

• 0.2 m

• 5 m

Answer explanation

Using Hooke's Law, F = kx, where F is the force, k is the spring constant, and x is the displacement. Rearranging gives x = F/k. Substituting F = 60 N and k = 120 N/m, we find x = 60/120 = 0.5 m.

Which factor listed below has the greatest effect on the period of a pendulum?

• Mass of the pendulum

• Length of the string

• Amplitude of the oscillations

Answer explanation

The period of a pendulum is primarily affected by the length of the string. A longer string results in a longer period, while the mass and amplitude have minimal impact on the period.

The amplitude of a particular wave is 4.0 m. The top-to-bottom distance of the disturbance is

• 2.0 m

• 4.0 m

• 8.0 m

• none of the above

Answer explanation

The amplitude of a wave is the distance from the rest position to the peak. Therefore, the total top-to-bottom distance is twice the amplitude: 2 x 4.0 m = 8.0 m.