Physics Test 3 Misconceptual Questions

A car traveling at a velocity v can stop in a minimum distance d. What would be the car's minimum stopping distance if it were traveling at a velocity of 2v? (a) d (b) sq 2d (c) 2d (d) 4d (e) 8d

d

When the speed of your car is doubled, by what factor does its kinetic energy increase? (a) the sq root of 2 (b) 2 (c) 4 (d) 8

(c)

A golf ball and an equal-mass bean bag are dropped from the same height and hit the ground. The bean bag stays on the ground while the golf ball rebounds. Which experiences the greater impulse from the ground? (a) the golf ball (b) the bean bag (c) both the same (d) not enough information

a

An astronaut is a short distance away from her space station without a tether rope. She has a large wrench. What should she do with the wrench to move toward the space station? (a) throw it directly away from the space station (b) throw it directly toward the space station (c) throw it toward the station without letting go of it (d) throw it parallel to the direction of the station's orbit (e) throw it opposite to the direction of the station's orbit

a

The space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay. For this collision, (a) only momentum is conserved (b) only kinetic energy is conserved (c) both momentum and kinetic energy are conserved (d) neither momentum nor kinetic energy is conserved

a

You are lying in bed and want to shut your bedroom door. You have a bouncy "superball" and a blob of clay, both with the same mass. Which one would be more effective to throw at your door to close it? (a) the superball (b) the the blob of clay (c) both the same (d) neither will work

a

You push a heavy crate down a ramp at a constant velocity. Only four forces act on the crate. Which force does the greatest magnitude of work on the crate? (a) friction (b) gravity (c) normal force (d) force of you pushing (e) net force

a

A car accelerates from rest to 30 km/h. Later, on a highway it accelerates from 30 km/h to 60 km/h. Which takes more energy, going from 0 to 30 or 30 to 60? (a) 0 to 30 (b) 30 to 60 (c) both are the same

b

A small boat coasts at constant speed under a bridge. A heavy sack of sand is dropped from the bridge onto the boat. The speed of the boat: (a) increases (b) decreases (c) does not change (d) without knowing the mass of the boat and the sand, we can't tell

b

You push very hard on a heavy desk, trying to move it. You do work on the desk: (a) whether or not it moves, as long as you are exerting a force (b) only if it starts moving (c) only if it doesn't move (d) never - it does work on you (e) none of the above

b

A baseball is pitched horizontally toward home plate with a velocity of 110 km/h. In which of the following scenarios does the baseball have the largest change in momentum? (a) the catcher catches the ball (b) the ball is popped straight up at a speed of 110 km/h (c) the baseball is hit straight back to the pitcher at a speed of 110 km/h (d) scenarios a and b have the same change in momentum (e) scenarios a, b, and c have the same change in momentum

c

A bowling ball is dropped from a height h onto the center of a trampoline, which launches the ball back up into the air. How high will the ball rise? (a) significantly less than h (b) more than h. The exact amount depends on the mass of the ball and the springiness of the trampoline (c) no more than h - probably a little less (d) cannot tell without knowing the characteristics of the trampoline

c

A man pushes a block up an incline at a constant speed. As the block moves up the incline, (a) its kinetic energy and potential energy both increase (b) its kinetic energy increases and its potential energy remains the same (c) its potential energy increases and its kinetic energy remains the same (d) its potential energy increases and its kinetic energy decreases by the same amount

c

A satellite in circular orbit around the Earth moves at constant speed. This orbit is maintained by the force of gravity between the Earth and the satellite, yet no work is done on the satellite. How is this possible? (a) no work is done if there is no contact between objects (b) no work is done because there is no gravity in space (c) no work is done if the direction of motion is perpendicular to the force (d) no work is done if objects move in a circle

c

Two identical billiard balls traveling at the same speed have a head-on collision and rebound. If the balls had twice the mass, but maintained the same size and speed, how would the rebound be different? (a) at a higher speed (b) at slower speed (c) no difference

c

A small car and a heavy pickup truck are both out of gas. The truck has twice the mass of the car. After you push both the car and the truck for the same amount of time with the same force, what can you say about the momentum and kinetic energy of the car and the truck? Ignore friction. (a) they have the same momentum and the same KE (b) the car has more momentum and more KE than the truck (c) the truck has more momentum and more KE than the car (d) they have the same momentum, but the car has more kinetic energy than the truck (e) they have the same kinetic energy, but the truck has more momentum than the car

d

A truck going 15 km/h has a head-on collision with a small car going 30 km/h. Which statement best describes the situation? (a) the truck has the greater change of momentum because it has the greater mass (b) the car has the greater change of momentum because it has the greater speed (c) neither the car nor the truck changes its momentum in the collision because momentum is conserved (d) they both have the same change in magnitude of momentum because momentum is conserved (e) none of the above is necessarily true

d

A ball is thrown straight up. At what point does the ball have the most energy? (a) at the highest point (b) when it is first thrown (c) just before it hits the ground (d) when the ball is halfway to the highest point of its path (e) everywhere; the energy of the ball is the same at all of these points

e

A skier starts from rest at the top of each of the hills shown in the figure. On which hill will the skier have the highest speed at the bottom assuming a small amount of friction:

the steepest hill and the longest hill