Physics Quiz 12/10

A dog is standing in the bed of a pickup truck. The bed is coated with ice, causing the force of friction between the dog and the truck to be zero. The truck is initially at rest, and then accelerates to the right, moving along a flat road. As seen from a stationary observer (watching the truck move to the right), the dog a a) does not move left or right, but the back of the truck moves towards the dog. b) moves to the left, as the truck moves to the right, causing the dog to slide towards the back of the truck. c) moves to the right, but not as quickly as the truck is moving to the right, causing it to slide towards the back of the truck. d) moves to the right at the same rate as the truck, so it doesn't slide.

A

A 20-ton truck collides with a 1500-lb car and causes a lot of damage to the car. During the collision a) the car and the truck have the same magnitude acceleration. b) the force on the truck due to the collision is slightly greater than the force on the car. c) the force on the track due to the collision is slightly greater than the force on the car.

B

A brick is resting on a rough incline as shown in the figure. The friction force acting on the brick, along the incline, is a) equal to the weight of the brick. b) less than the weight of the brick. c) zero. d) greater than the weight of the brick.

B

On a horizontal frictionless floor, a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN. As a result of this push, which statement could be true? a) The worker will accelerate at 1.08 m/s^2 and the box will accelerate at 2.17 m/s^2, but in opposite directions. b) The worker will accelerate at 2.17 m/s^2 and the box will accelerate at 1.08 m/s^2, but in opposite directions. c) The box will not move because the push is less than its weight. d) The worker and box will both have an acceleration of 1.08 m/s^2, but in opposite directions.

B

Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined plane and allowed to slide down from rest. a) It takes the lighter object 10 times longer to reach the bottom of the incline than the heavier object. b) The two objects reach the bottom of the incline at the same time. c) It takes the heavier object 5 times longer to reach the bottom of the incline than the lighter object. d) It takes the heavier object 10 times longer to reach the bottom of the incline than the lighter object.

B

In order to lift a bucket of concrete, you must pull up harder on the bucket than the bucket pulls down on you. True or false

False

An object is moving to right, and experiencing a net force that is directed to the right. The magnitude of the function is decreasing with time. The speed of the object is

Increasing