Projectile, Dynamics

Multiple Choice

At what point is v_y= 0 m/s?

• A

• B

• C

• D

• None of these points

Multiple Choice

At what point is v_x= 0 m/s?

• A

• B

• C

• D

• None of these points

Multiple Choice

Suppose Lemming A runs off the edge of the cliff at 2 m/s and Lemming B runs off the edge at 1 m/s. Which will hit the ground farther from the base of the cliff?

• A

• B

• Both at the same distance

Multiple Choice

What happens to the vertical velocity of a projectile as it goes up?

• increases

• decreases

• stays the same

• none of these

Multiple Choice

A skateboarder rolls off a bridge into the river as shown. If the skateboarder was originally moving at 7.0 m/s, how much time did the skateboarder spend in the air?

• 1.3 s

• 0.79 s

• 38.5 s

• 0.70 s

• Not enough information given.

Multiple Choice

Poor Tugg Speedman fell out a helicopter that was moving at a horizontal speed of 80 m/s. Luckily, Tugg landed in a pool 2.5 seconds later. Assuming there was no air resistance, what was the horizontal distance between where Tugg came out of the helicopter and the pool?

• 160 m

• 200 m

• 80 m

• 120 m

Multiple Choice

When backed up 4th and long, the Eagles decide to punt the football. The ball is kicked so that it lifts off with an angle to the ground of 39 degrees. The initial speed is 31 m/s. What is the initial horizontal speed of the football?

• 19.5 m/s

• 24 m/s

• 33 m/s

• 14.5 m/s

Multiple Choice

Valerie is standing on a ladder picking apples in her grandfather's orchard. As she pulls each apple off the tree, she tosses it into a basket that sits on the ground 3.0 m below at a horizontal distance of 2.0 m from Valerie. How fast must Valerie throw the apples (horizontally) in order for them to land in the basket?

• 3.3 m/s

• 7.4 m/s

• 4.7 m/s

• 2.6 m/s

Multiple Choice

A ball is thrown and follows the parabolic path shown above. Air friction is negligible. Point Q is the highest point on the path. Points P and R are the same height above the ground. Which of the following diagrams best shows the direction of the acceleration of the ball at point P?

Fill in the Blanks

a 43 kg box is on a frictionless 32 degree inclined plane. What is the F_N

Fill in the Blanks

a 43 kg box is on a 32 degree inclined plane with a friction coefficient of .23 What is the F_net

Fill in the Blanks

A 20 kg box is pulled up an incline of 60 degrees on a surface that has a frictional coefficient of .09. With an applied force of 221 N. What is the resulting force

Multiple Choice

If an object is at rest on an inclined plane, which of the following forces is greatest?

• Normal Force
• Friction
• Weight
• Both Normal Force and Weight are equal, so they both are the greatest.

Multiple Choice

Which of the following is the best expression for the Normal Force?

• F_N = mg cos(ϴ)

• F_N = mg sin(ϴ)

• F_N = mg sin(180-ϴ)

• F_N = mg cos(90-ϴ)

Multiple Choice

A 3.0-kg block slides on a frictionless 20° inclined plane. A force of 16 N acting parallel to the incline and up the incline is applied to the block. What is the acceleration of the block?

• 2 m/s^2 down the incline
• 5.3 m/s^2 up the incline
• 2 m/s^2 up the incline
• 3.9 m/s^2 down the incline

Multiple Choice

A 10kg block with an initial velocity of 10m/s slides 10m across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about

• 5N

• 10N

• 25N

• 50N

Multiple Choice

Are these two situations the same?

• Yes, same magnitude of force

• No, different type of force

• Not enough information

Multiple Choice

A load of 650 newtons is lifted with this pulley. What is the effort required to do this work?

• 300

• 325

• 600

• 650

Multiple Choice

Which of the following is Newton's Law on Gravitation?

• F=Gm₁m₂/r
• F = Gm₁m₂/r²
• F = Gm₁m₂/2r
• F = m₁m₂/2r

Multiple Choice

Two factors effecting the magnitude of the force of gravity between 2 objects are...

• mass and distance 
• mass and matter
• distance and weight 
• weight and mass

Multiple Choice

If I double the distance between two objects, what happens to their gravitational Force?

• 4x bigger
• 4x smaller
• 2x bigger
• 2x smaller

Multiple Choice

Two objects are attracted to each other with 36 N of gravitational force.
What would the force between them be if the distance between them were doubled?

• 9
• 18
• 72
• 144

Multiple Choice

Calculate the gravitational force between two objects when they are 0.750m apart. Each object has a mass of 5.00kg.

• 2.96x10^-7N

• 3.00x10^-6N

• 2.22x10^-9N

• 2.23x10^-8N

Multiple Choice

three laws derived by Johannes Kepler that describe the properties of all orbiting satellites

• Kepler’s laws of planetary motion

• All orbiting satellites must have a circular orbit.

• All orbiting satellites must have a constant speed.

• All orbiting satellites must have the same orbital period.

Fill in the Blanks

Kepler's 3rd law states that a planet's period is proportional to its distance from the sun.

A planet is 3.9 AU from the Sun. Find the period of the planet (p) in years. Do NOT include units in your answer.

Multiple Choice

Which planet will take the least amount of time to revolve around the Sun?

• Mercury

• Venus

• Earth

• Mars