PU3 Overview

Multiple Choice

Why is time considered the big link between the x-plane and y-plane in kinematics problems involving river boats?

• Because time determines the direction of motion

• Because time is the only variable that is the same in both planes

• Because time changes with acceleration

• Because time is only relevant in the y-plane

Multiple Choice

Which equation would you use to find "time"?

• $$\Delta x=vt$$  

• $$v=v_0+at$$  

• $$\Delta x=v_0t+\frac{1}{2}at^2$$  

• $$v^2=v_0^2+2a\Delta x$$  

• $$\Delta x=\frac{1}{2}\left(v_0+v\right)t$$  

Multiple Choice

If the velocity of the river current increased to 2.5 m/s, how would this affect the distance you are washed downstream?

• You would be washed a shorter distance downstream

• You would be washed a longer distance downstream

• The distance would remain the same

• You would not be washed downstream at all

Multiple Choice

Which of the following statements about freefall is correct?

• The only force acting is gravity.

• There is acceleration in the horizontal direction.

• Motion in one dimension affects the other.

• Acceleration due to gravity is 5 m/s^2.

Multiple Select

Which of the following are true about the x-direction and y-direction in projectile motion?

• Acceleration in x-direction is 0 m/s^2.

• Acceleration in y-direction is -9.8 m/s^2.

• Final velocity in x-direction is same as initial.

• Displacement in y-direction is always positive.

Multiple Choice

What happens to the vertical velocity of a projectile at its highest point?

• It becomes zero.

• It is at maximum.

• It is negative.

• It is equal to the horizontal velocity.

Multiple Choice

Which of the following best describes the direction of centripetal acceleration for an object in circular motion?

• It is always tangent to the circle.

• It is always outward from the center of the circle.

• It is always inward toward the center of the circle.

• It is always perpendicular to the velocity.

Check your notes

Multiple Choice

What is the horizontal acceleration of a projectile?

• 0 m/s²
• -9.8 m/s²

Multiple Choice

When is gravity the strongest?

• At the launch

• Halfway point of the projectile motion

• At the very end of the projectile motion

• Gravity is always constant

Multiple Choice

What is the direction of the acceleration for any projectile?

• The direction the projectile is traveling.

• Down

• Up

• Sideways

Multiple Choice

At which point is our object slowing down?

• B

• D

• E

• All points

Multiple Choice

Which of the following would NOT be considered a projectile? 

• a cannonball thrown straight up
• a cannon ball rolling down a slope
• a cannonball rolling off a table
• a cannonball thrown in the air