Physics ch 5

When an object reaches terminal velocity its acceleration is

Selected: a. 0 m/s2. b. 4.9 m/s2. c. 9.8 m/s2.

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is

Selected: a. 10 times as much as the force on the 1-kg book.This answer is correct. b. zero. c. the same as the force on the 1-kg book.

A tennis ball and a solid steel ball with the same diameter are dropped at the same time. Which ball has the greater force acting on it?

Selected: a. The steel ball b. The tennis ball c. They both have the same force acting on them.

Accelerations are produced by

Selected: a. forces b. velocities c. accelerations. d. masses. e. none of the above

A block is at rest on an incline. The force of friction necessary to prevent the block from sliding increases when the incline angle is

Selected: a. increased. b. decreased. c. neither A nor B (Force of friction stays the same.)

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

Selected: a. its weight.This answer is correct. b. less than its weight. c. more than its weight.

A force of 3 N accelerates a mass of 3 kg at the rate of 1 m/s2. The acceleration of a mass of 6 kg acted upon by

a force of 6 N is a. twice as much. b. half as much. Selected: c. the same. d. none of the above

An apple weighs 1 N. The net force on the apple when it is in free fall is

a. 0 N. b. 0.1 N. Selected: c. 1 N.This answer is correct. d. 9.8 N. e. none of the above

The terminal speed for a person parachuting (with the chute open) is about

a. 0 km/h. Selected: b. 15 km/h. c. 150 km/h. d. 1500 km/h.

Which of the following would exert the most pressure on the ground?

a. A woman standing in running shoes b. A woman standing on skis Selected: c. A woman standing in high-heel shoes

Suppose a cart is being moved by a force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration?

a. It quarters. Selected: b. It halves.This answer is correct. c. It stays the same. d. It doubles. e. It quadruples.

If the force acting on a cart doubles, what happens to the cart's acceleration?

a. It quarters. b. It halves. c. It stays the same. Selected: d. It doubles. e. It quadruples.

A tennis ball and a solid steel ball with the same diameter are dropped at the same time. In the absence of air resistance, which ball has the greater acceleration?

a. The steel ball b. The tennis ball Selected: c. They both have the same acceleration.

How does acceleration of an object change in relation to its mass? It is

a. directly proportional. b. Acceleration doesn't depend on mass at all. Selected: c. inversely proportional.

A speeding truck locks it brakes and it skids to a stop. If the truck's total mass were doubled, its skidding distance would be

a. half as far. b. nearly as far, but not quite. Selected: c. the same. d. twice as far. e. four times as far.

You are on a frozen pond, and the ice starts to crack. If you lie down on the ice and begin to crawl, this will

a. increase the pressure on the ice. Selected: b. decrease the pressure on the ice.This answer is correct. c. increase the total force on the ice. d. decrease the total force on the ice.

Consider a ball rolling down the decreasing slope inside a semicircular bowl (the slope is steep at the top rim, gets less steep toward the bottom, and is zero (no slope) at the bottom). As the ball rolls from the rim downward toward the bottom, its rate of gaining speed

a. increases b. remains the same Selected c. decreases

When the angle of an incline with a block resting on it increases, the normal support force

a. increases b. stays the same Selected: c. decreases

The acceleration produced by a net force on an object is

a. inversely proportional to the mass of the object. b. directly proportional to the magnitude of the net force. c. in the same direction as the net force. Selected: d. all of the above e. none of the above

Suppose a particle is accelerated through space by a constant 10-N force. Suddenly the particle encounters a second force of 10-N in a direction opposite to that of the first force. The particle

a. is brought to a rapid halt. b. theoretically accelerates to speeds approaching the speed of light. Selected: c. continues at the speed it had when it encountered the second force. d. gradually decelerates to a halt. e. none of the above

Aunt Minnie throws a rock downward, and air resistance is negligible. Compared to a rock that is dropped, the acceleration of the rock after it is thrown is

a. less Selected: b. the same c. more

When a woman stands with two feet on a scale, the scale reads 280 N. When she lifts one foot, the scale reads

a. less than280 N. b. more than 280N. Selected: c. 280 N.

Suppose the force of friction on a sliding object is 25 N. The force needed to maintain a constant velocity is

a. more than 25 N. Selected: b. 25 N c. less than 25 N

The unit of pressure is

a. newtons per meter. Selected: b. newtons per square meter (or pascals). c. the newton. d. the meter. e. meters per second squared.

As a care package falls from a high-flying stationary helicopter, its velocity increases and its acceleration

a. remains the same Selected: b. decreases c. increases

A heavy person and a light person parachute together and wear the same size parachutes. Assuming they open their parachutes at the same time, which person reaches the ground first?

a. the light person Selected: b. the heavy person c. Neither -- they both reach the ground together.

The reason a tennis ball and a solid steel ball will accelerate at the same rate, in the absence of air resistance, is that

a. they have the same mass. b. the ball with the larger force has the smaller mass. Selected: c. the ball with the larger force also has the larger mass. d. the force acting on them is the same. e. none of the above

Pressure is defined as

a. time per area. b. velocity per time. c. force per time. Selected: d. force per area. e. distance per time.

An object has a constant mass. A constant force on the object produces constant

a. velocity. Selected: b. acceleration. c. both A and B d. none of the above

A push on a 1-kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kilogram brick, one would have to push

a. with 100 times as much force. Selected: b. with 10 times as much force. c. with just as much force. d. with 1/10 the amount of force. e. none of the above