Fundamentals of Physics Chapter 4

An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is A) 0 N. B) 0.1 N. C) 1 N. D) 9.8 N. E) none of the above

A) 0 N.

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same A) mass. B) volume. C) weight. D) all of the above E) none of the above

E) none of the above

A large and a small person wish to parachute at equal terminal velocities. The larger person should A) get a larger parachute. B) jump lightly. C) pull upward on the supporting strands to decrease the downward net force. D) jump first from the plane.

A) get a larger parachute.

A skydiver's terminal velocity will be greatest if she falls A) head first. B) lying flat on her back. C) lying flat on her stomach. D) with her parachute open.

A) head first.

A ball thrown straight upward takes 10 seconds for its up-and-down round trip. Because of air resistance, the time taken for the ball just to go up is A) less than 5 s. B) 5 s. C) more than 5 s.

A) less than 5 s.

A 1-kg rock that weighs 10 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is A) less than 10 N. B) 10 N. C) more than 10 N.

B) 10 N.

A rock is thrown vertically into the air. At the top of its path, its acceleration is A) zero. B) 10 m/s2. C) between 0 and 10 m/s2. D) greater than 10 m/s2.

B) 10 m/s2.

If you are driving at 20 m/s and slam on your brakes and skid at 0.5g to a full stop, the skidding time is about A) 3 s. B) 4 s. C) 5 s. D) 6 s. E) greater than 6 s.

B) 4 s.

Suzie Skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration A) increases. B) decreases. C) remains unchanged regardless of air resistance.

B) decreases.

Your weight as measured on your bathroom scale is A) equal to your mass. B) the force due to gravity on you. C) a property of mechanical equilibrium. D) all of the above

B) the force due to gravity on you.

When a constant and sustained upward force acts on a rocket, its acceleration increases mainly because A) gravity becomes weaker with increased distance. B) the mass of the rocket decreases as fuel is burned. C) No way, for acceleration would be constant

B) the mass of the rocket decreases as fuel is burned.

A boulder following a straight-line path at constant velocity has A) a net force acting upon it in the direction of motion. B) zero acceleration. C) no forces acting on it. D) none of the above

B) zero acceleration.

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was A) 1.2 m/s. B) 15 m/s. C) 30 m/s. D) 45 m/s.

C) 30 m/s.

A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time? A) 100 m B) 200 m C) 300 m D) 400 m

C) 300 m

The human body can withstand an acceleration of 10 g under certain conditions. What net force would produce this acceleration for a 50-kg person? A) 500 N B) 2500 N C) 5000 N D) 25,000 N E) none of the above

C) 5000 N

A heavy block at rest is suspended by a vertical rope. When the block accelerates upward by the rope, the rope tension A) is less than its weight. B) equals its weight. C) is greater than its weight.

C) is greater than its weight.

A ball is thrown vertically into the air. Because of air resistance, its time coming down compared to its time going up is A) less. B) the same. C) more.

C) more.

When you stand at rest with your left foot on one bathroom scale and your right foot on a similar scale, each of the scales will A) read half your weight. B) read your weight. C) show readings that when added equal your weight. D) cancel your weight.

C) show readings that when added equal your weight.

Two factors that greatly affect air resistance on falling objects are frontal area and A) mass. B) weight. C) speed.

C) speed.

What horizontally-applied force will accelerate a 400-kg crate at 1 m/s2 across a factory floor against a friction force half its weight? A) 600 N B) 1600 N C) 2000 N D) 2400 N E) none of the above

D) 2400 N

Suzie Skydiver, who weighs 500 N, reaches a terminal velocity of 90 km/h. The air resistance on Suzie is then A) 90 N. B) 250 N. C) 410 N. D) 500 N. E) none of the above

D) 500 N.

Recall Galileo's Leaning Tower experiment. With negligible air resistance, a heavy and a light object fall A) with equal accelerations. B) with the same increases in speed. C) to the ground in equal times. D) all of the above

D) all of the above

The brakes of a speeding truck are slammed on and it skids to a stop. If the truck were heavily loaded so that it had twice the total mass, the skidding distance would be A) half as far. B) 1.5 times as far. C) twice as far. D) 4 times as far. E) the same.

E) the same.