Concept Test

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

c. 2

Exert 100 J in 50 s and your power output is a. 1/4 W b. 1/2 W c. 2 W d. 4 W e. more than 4 W

c. 2 W

An elephant and a feather fall from a tree through the air to the ground below. The amount of air-resistance is greater on the a. elephant b. feather c. is the same on each

a. elephant

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

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

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

a. agree that it can't be done

A clerk can lift containers a vertical distance of 1 m or can roll them up a 2-m-long ramp to the same elevation. With the ramp, the applied force required is about a. half as much b. twice as much c. the same

a. half as much

A ball is projected into the air with 100 J of kinetic energy that is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is a. less than 100 J b. more then 100 J c. 100 J

a. less than 100 J

In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the a. moon? b. earth? c. planet jupiter?

a. moon?

An object that has kinetic energy must be a. moving b. falling c. at an elevated position d. at rest e. none of these

a. moving

If you push an object just as far while applying twice the force, you do a. twice as much work b. four times as much work c. the same amount of work

a. twice as much work

A rock is thrown vertically into the air. At the top of its path, its acceleration in meters per second per second is about a. 0 b. 10 c. between 0 and 10 d. greater than 10 e. none of these

b. 10

It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box? a. 4 N b. 10 N c. 40 N d. 160 N e. none of these

b. 10 N

If a free falling object were somehow equipped with a speedometer, its speed reading would increase each second by about a. 5 m/s b. 10 m/s c. 15 m/s d. a variable amount. e. depends on its initial speed

b. 10 m/s

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 as the force on the 1-kg book c. zero

b. 10 times as much as the force on the 1-kg book

A push on a 1-kg brick accelerates the brick, 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 e. none of these

b. 10 times as much force

A 2-kg mass has 40 J of potential energy with respect to the ground. Approximately how far is it located above the ground? a. 1 m b. 2 m c. 3 m d. 4 m e. none of these

b. 2 m

A girl pulls on a 10-kg wagon with a constant force of 30 N. What is the wagon's acceleration in meters per second per second? a. 0.3 b. 3.0 c. 10 d. 30 e. 300

b. 3.0

Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power does the elevator use? a. 20 W b. 50 W c. 100 W d. 1000 W e. 20,000 W

b. 50 W

In raising a 5000-N piano with a pulley system, for every 1 m of rope pulled down, the piano rises 0.1 m. Ideally, this means the force needed to lift it is about a. 50 N b. 500 N c. 5000 N d. not enough information given to estimate

b. 500 N

A flower pot of mass m falls from rest to the ground below, a distance h. Which statement is correct? a. The speed of the pot when it hits the ground is proportional to h. b. The KE of the pot when it hits the ground is proportional to h. c. The KE of the pot when it hits the ground does not depend on m. d. The speed of the pot when it hits the ground depends on m. e. None of these are correct

b. The KE of the pot when it hits the ground is proportional to h.

Which has the greater mass? a. king-size pillow b. automobile battery c. both about the same

b. automobile battery

Suppose you're coasting in a car at 60 km/h and apply the brakes until you slow to 40 km/h. When you suddenly release the brake, the car tends to a. momentarily regain its higher initial speed b. continue moving at 40 km/h in the absence of forces c. decrease in speed whether or not other forces act

b. continue moving at 40 km/h in the absence of forces

An object is propelled along a straight-line path by a force. If the net force were doubled, its acceleration would a. quadruple b. double c. stay the same d. halve e. none of these

b. double

A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of a. energy b. power c. both of these d. none of these

b. power

Which has greater kinetic energy, a car traveling at 30 km/h or a car of half the mass traveling at 60 km/h? a. the 30-km/h car b. the 60-km/h car c. both have the same kinetic energy

b. the 60-km/h car

An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high, it gains a. four times as much potential energy b. twice as much potential energy c. neither of these

b. twice as much potential energy

A 1-kg mass at the Earth's surface weighs about a. 1 N b. 5 N c. 10 N d. 12 N e. none of these

c. 10 N

A bag of groceries that has a mass of 10 kilograms weighs about a. 1 N b. 10 N c. 100 N d. 1000 N e. more than 1000 N

c. 100 N

A baseball player bats a ball with a force of 1000 N. The ball exerts a reaction force against the bat of a. less than 1000 N b. more than 1000 N c. 1000 N

c. 1000 N

Consider a hydraulic press. When the input piston is depressed 20cm, the output piston is observed to move 1 cm. On the same press, an input force of 1N can raise no more than a. 1 N b. 20 N c. 20 N d. 21 N

c. 20 N

A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of a. less than 40 J b. more than 40 J c. 40 J

c. 40 J

A person is attracted toward the center of Earth by a 500-N gravitational force.The force of attraction of the Earth toward the person is a. very, very small b. very, very large c. 500 N

c. 500 N

A MAck truck and a Volkswagen traveling at the same speed collide head-on. The impact force is greatest on the a. volkswagen b. mack truck c. is the same for both

c. is the same for both

A kilogram is a measure of an object's a. weight. b. force. c. mass d. gravity e. center of mass

c. mass

No work is done by gravity on a bowling ball that rolls along a bowling alley because a. no force acts on the ball b. no distance is covered by the ball c. the force on the ball is at right angles to the ball's motion d. no potential energy is being converted to kinetic energy e. its kinetic energy remains constant

c. the force on the ball is at right angles to the ball's motion

A 50-kg sack is lifted 2 m in the same time as a 25-kg sack is lifted 4 m. The power expended in raising the 50-kg sack compared to the power used to lift the 25-kg sack is a. twice as much b. half as much c. the same

c. the same

When an object is lifted 10m, it gains a certain amount of potential energy. If the same object is lifted 20 m, its potential energy gain is a. less b. the same c. twice as much d. four times as much e. more than four times as much

c. twice as much

A 1000-kg car and a 2000-kg car are hoisted the same distance in a gas station. Raising the more massive car requires a. less work b. as much work c. twice as much work d. four times as much work e. more than four times as much work

c. twice as much work

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has a. 4 times the KE b. 8 times the KE c. 12 times the KE d. 16 times the KE

d. 16 times the KE

A car has a mass of 1000 kg and accelerates at 2 m/s/s. What is the magnitude of the force exerted on the car? a. 500 N b. 1000 N c. 1500 N d. 2000 N e. none of these

d. 2000 N

A TV set is pushed a distance of 2 m with a force of 20 N that is in the same direction as the set moves. How much work is done on the set a. 2 J b. 10 J c. 20 J d. 40 J e. 80 J

d. 40 J

A 2-kg mass if held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground? a. 20 J b. 40 J c. 60 J d. 80 J e. none of these

d. 80 J

The power expended with a barbell is raised 2.0 m in 2 s is a. 1 W b. 4 W c. 8 W d. dependent on the mass of the barbell

d. dependent on the mass of the barbell

An object that has potential energy may have this energy because of its a. speed b. acceleration c. momentum d. location e. none of these

d. location

While a car travels around a circular track at constant speed, its a. acceleration is zero. b. velocity is zero. c. both of these d. none of these

d. none of these

One object has twice as much mass as another object, and also has twice as much a. inertia b. velocity c. gravitational acceleration d. volume e. all of these

d. volume

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the a. weight of the arrow b. air resistance against the bow c. friction of the ground against the archer's feet d. grip of the archer's hand on the bow e. arrow's push against the bowstring

e. arrow's push against the bowstring

When a car is braked to a stop, its kinetic energy is transformed to a. stopping energy b. potential energy c. energy of motion d. energy of rest e. heat

e. heat

Compared with 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 these. e. none of these.

e. none of these.

The breaks are slammed on a speeding truck and it skids to a stop. If the truck were heavily loaded so it had twice the total mass, the skidding distance would be a. 1/2 as far b. 1 1/2 times as far c. 2 times as far d. 4 times as far e. the same

e. the same