PHYS-1401 (Test II)

A ball is thrown vertically into the air. Because of some air resistance, its speed when it returns to its starting level compared with its initial speed is a) less. b) the same. c) more. 2.18

a) less.

In which cases would you have the largest mass of gold? If your chunk of gold weighed 1 N on the a) moon. b) Earth. c) Jupiter. 1.7

a) moon.

A 10-N block and a 1-N block lie on a horizontal frictionless table. To provide them with equal horizontal acceleration, we would have to push with a) equal forces on each block. b) 10 times as much force on the heavier block. c) 10 squared or 100 times as much force on the heavier block. d) 1/10 as much force on the heavier block. e) none of these. 1.21

b) 10 times as much force on the heavier block.

An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is a) 0 N. b) 5 N. c) 25 N. d) 150 N. 1.13

b) 5 N.

A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about a) 1/2 N. b) 1 N. c) 5 N. d) 7.5 N. e) 10 N. 2.2

e) 10 N.

A vehicle that weights 400 N on the surface of the Earth is traveling in outer space at a speed of 400 m/s. It can be stopped by applying a constant force of 20 N for a) 2 seconds. b) 4 seconds. c) 80 seconds. d) 400 seconds. e) 800 seconds 3.8

e) 800 seconds

If an object of constant mass experiences a constant net force, it will have a constant a) velocity. b) speed. c) acceleration. d) position. e) more than one of the above. 2.13

e) more than one of the above.

An apple weighs 1 N. When 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 these. 1.15

a) 0 N.

A 10-kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block in meters per second per second is a) 1. b) 2. c) 5. d) 10. e) none of these. 2.7

a) 1.

A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope? a) 400 N. b) 600 N. c) 800 N. d) zero. e) none of these. 3.5

a) 400 N

Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by: a) Arnold, of course. b) Suzie, surprisingly. c) both the same, interestingly enough. 3.1

a) Arnold, of course.

A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the a) Volkswagen. b) Mack truck. c) same for both. 3.3

a) Volkswagen

Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on an isolated piece of tissue paper with his best punch. The tissue paper is held in midair - no wall, no tricks. You a) agree that it can't be done. b) have reservations about this assertion. c) disagree, for a good punch easily delivers this much force. 3.4

a) agree it can't be done.

The newton is a unit of a) force. b) mass. c) density. d) inertia. 1.6

a) force.

A coconut and a feather fall from a tree through the air to the ground below. The amount of air-resistance force is a) greater on the coconut. b) greater on the feather. c) the same on each. 3.9

a) greater on the coconut

If one object has twice as much mass as another object, it also has twice as much a) inertia. b) velocity. c) acceleration due to gravity. d) volume. e) all of these. 1.3

a) inertia.

A ball thrown straight upward takes 10 seconds to go up and return to the ground. Because of air resistance, the time taken for the ball just to go up is a) less than 5 s. b) more than 5 s. c) 5 s. 2.22

a) less than 5 s.

Two objects of the same size, but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to achieve its terminal velocity first will be the a) lighter object. b) heavier object. c) both hit at the same time. d) not enough information. 3.12

a) lighter object.

A force is a vector quantity because it has both a) magnitude and direction. b) mass an acceleration. c) action and reaction counterparts. 1.10

a. magnitude and direction.

A push on a 1-kg brick accelerates it. Neglecting friction, to equally accelerate a 10-kg brick, one would have to push with a) just as much force. b) 10 times as much force. c) 100 times as much force. d) one-tenth the amount of force. 1.20

b) 10 times as much force.

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is a) the same as the force on the 1-kg book. b) 10 times as much. c) one-tenth as much. d) zero. 1.11

b) 10 times as much.

A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration in meters per second per second when taking off? a) 0.25. b) 1. c) 2. d) 4. e) none of these. 1.26

c) 2

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. e) none of these. 2.10

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. e) none of these. 2.9

c) 300 m.

A 10-N falling object encounters 4 N of air resistance. The net force on the object is a) 0 N. b) 4 N. c) 6 N. d) 10 N. e) none of these. 1. 14

c) 6 N.

A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface? a) less than 6 N. b) more than 6 N. c) 6 N. d) need more information to say. 1.25

c) 6 N.

A falling skydiver of mass 100 kg experiences 500 N of air resistance. The acceleration of the skydiver is a) 0.2 g. b) 0.3 g. c) 0.4 g. d) 0.5 g. e) more than 0.5 g. 2.23

d) 0.5 g

What horizontally-applied force will accelerate a 400-kg crate at 1 m/s^2 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 these. 2.11

d) 2400 N.

A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is a) 300 N downward. b) 500 N downward. c) 800 N downward. d) 300 N upward. e) 500 N upward. 2.17

d) 300 N upward.

A vehicle that weighs 4000 N on the surface of the Earth is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is a) 20 N. b) 40 N. c) 400 N. d) 4000 N. e) more than 4000 N. 3.7

d) 4000 N

A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters 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 a) 5 N. b) 10 N. c) 25 N. d) 50 N. e) none of these. 2.6

d) 50 N.

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much a) inertia. b) mass. c) volume. d) all of these. e) none of these. 1.1

d) all of these.

A lightweight feather slides off a table and falls through the air until it reaches the floor. During the time of its fall, its acceleration a) keeps increasing. b) keeps decreasing. c) never changes. d) is sometimes zero. 2.16

d) is sometimes zero.

The force exerted on the tires of a car to directly accelerate it along a road is exerted by the a) engine. b) tires. c) air. d) road. e) none of these 3.6

d) road.

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) 1.2 as far. b) 1 1/2 time as far. c) 2 times as far. d) 4 times as far. e) the same. 2.3

e) the same.

Strange as it may seem, it is just as hard to accelerate a car on a level surface on the moon as it is here on the Earth. This is because a) the mass of the car is independent of gravity. b) the weight of the car is independent of gravity. c) Nonsense! A car is much more easily accelerated on the moon than on earth. 1.4

a) the mass of the car is independent of gravity.

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity a) the object accelerates in the direction of the applied force. b) the object accelerates opposite the direction of the applied force. c) the friction force increases. d) two of the above. e) none of the above. 2.14

a) the object accelerates in the direction of the applied forces.

A car traveling at 22 m/s comes to an abrupt halt in 0.1 second when it hits a tree. What is the deceleration in meters per second of the car? a) 110 b) 220 c) 800 d) 880 e) can't be solved without the mass of the car. 2.7

b) 220

A ride on a roller-coaster car containing 6 passengers takes 3 minutes. Neglecting friction, a similar ride with 12 passengers aboard would take a) 1.5 minutes. b) 3 minutes. c) 6 minutes. d) 18 minutes. 1.5

b) 3 minutes.

An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, how much does the rock weigh? a) 1 N. b) 4 N. c) 4.9 N. d) 5 N. 2.24

b) 4 N.

A rock is thrown vertically into the air. At the top of its path, its acceleration is a) zero. b) 9.8 c) between 0 and 9.8 d) greater than 9.8 1.24

b) 9.8

A 1-kg rock that weight 9.8 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is halfway to the top of its path is a) less than 9.8 N b) 9.8 N c) more than 9.8 N 2.1

b) 9.8 N

If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is a) about 3. b) about 4. c) about 5. d) about 6. e) more than 6. 2.8

b) about 4.

Your car is coasting on level ground at 60 km/h and you apply the brakes until the car slows to 40 km/h. If you suddenly release the brakes now, the car tends to a) momentarily regain its higher initial speed. b) continue moving at 40 km/h. c) decrease in speed if no other forces act. 1.17

b) continue moving at 40 km/h.

Two objects of the same size, but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the a) lighter object. b) heavier object. c) both hit at the same time. d) not enough information. 3.11

b) heavier object.

Two tennis balls fall through the air from a tall building. One of them is filled with lead pellets. The ball to reach the ground first is the a) regular ball. b) lead-filled ball. c) same for both. 2.19

b) lead-filled ball.

The maximum acceleration of a car while towing a second car twice its mass, compared to its acceleration with no car in tow, is a) one half. b) one third. c) one fourth. d) the same. e) none of these. 1.16

b) one third.

Your weight is a) equal to your mass. b) the gravitational attraction force between you and the Earth. c) a property of mechanical equilibrium. d) all of these. 1.2

b) the gravitational attraction force between you and the Earth.

A rock weighs 30 N on Earth. A second rock weighs 30 N on the moon. Which of the two rocks has the greater mass? a) the one on Earth. b) the one on the moon. c) they have the same mass. d) not enough information to say. 1.8

b) the one on the moon.

When a falling object has reached its terminal velocity, its acceleration is a) constant. b) zero. c) g. 2.15

b) zero.

The human body can, under certain conditions, withstand an acceleration of 10 g. What net force would produce this acceleration of a 50-kg person? a) about 500 N. b) about 2500 N. c) about 5000 N. d) about 25,000 N. e) none of these. 2.12

c) about 5000 N.

Hang from a pair of gym rings and the upward support forces of the rings will always a) each be half your weight. b) each be equal to your weight. c) add up equal to your weight. 1.19

c) add up equal to your weight.

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is a) less than its weight. b) more than its weight. c) equal to its weight. 1.23

c) equal to its weight.

If a non-rotating object has no acceleration, then we can say for certain that it is a) at rest. b) moving at a constant non-zero velocity. c) in mechanical equilibrium. d) all of these. e) none of these. 1.18

c) in mechanical equilibrium.

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. 2.21

c) more.

An object's weight may be properly expressed in units of a) meters. b) kilograms. c) newtons. d) cubic centimeters. 1.9

c) newtons.

A heavy rock and a light rock of the same size are falling through the air from a tall building. The one that encounters the greatest air resistance is the a) light rock. b) heavy rock. c) same for both. 2.20

c) same for both.

Two factors that greatly affect air resistance on falling objects are the a) size and mass of the object. b) size and weight of the object. c) size and speed of the object. 3.10

c) size and speed of the object.

A rocket becomes progressively easier to accelerate as it travels upward from the ground mainly because a) gravity becomes weaker with increased distance. b) the applied force on the rocket increases as burning of fuel progresses. c) the mass of the rocket decreases as fuel is burned. 1.22

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

An automobile and a baby carriage traveling at the same speed collide head-on. The impact force is a) greater on the automobile. b) greater on the baby carriage. c) the same for both 3.2

c) the same for both.

An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be a) half as much. b) the same. c) twice as much. d) four times as much. 1.12

c) twice as much.