the energy supplied to the machine

1. If an object weighs 39.2 N on Earth, what is its mass?

A. 8 N

B. 384.16 kg

C. 4 kg

D. 78.4 N

 

 

2. How much time should be allowed for a 392-km car trip if the car will be traveling at

120 km/h?

A. 5.12 hours

B. 3.27 hours

C. 2.72 hours

D. 0.31 hours

 

 

3. A machine has an efficiency of 91%. If the energy supplied to the machine is 4,000 watts,

what is the amount being used for work?

A. 4,091 watts

B. 43.96 watts

C. 360 watts

D. 3,640 watts

 

1. What is the kinetic energy of an object that has a mass of 20 kilograms and a speed of

2.8 m/s?

A. 56 J

B. 22.8 J

C. 17.2 J

D. 78.4 J

 

 

2. If a gas has a gage pressure of 206 kPa, its absolute pressure is approximately

A. 2,060 kPa.

B. 306 kPa.

C. 106 kPa.

D. 20.6 kPa.

 

 

3. According to Ptolemy’s model of the movement of celestial bodies,

A. the earth rotates around the sun.

B. the sun is the center of the universe.

C. the earth rotates around the moon.

D. planets orbit in circular paths around the earth.

 

 

 

1. What force is required to accelerate a body with a mass of 18 kilograms at a rate

of 36 m/s2?

A. 2 N

B. 54 N

C. 648 N

D. 6,350 N

 

 

2. Oil flows upward in the wick of a lantern because of the liquid property called

A. viscosity.

B. capillarity.

C. meniscusity.

D. density.

 

 

3. A car travels from Boston to Hartford in 4 hours. The two cities are 240 kilometers apart.

What was the average speed of the car during the trip?

A. 4 km/hour

B. 36 km/hour

C. 60 km/hour

D. 960 km/hour

 

 

1. Which of the following is the term used to describe a body’s resistance to a change in

motion?

A. Inertia

B. Acceleration

C. Gravity

D. Mass

 

 

2. If the speed of an object changes from 121 m/s to 98 m/s during a time interval of 12 s,

what is the acceleration of the object?

A. -276 m/s2

B. -1.92 m/s2

C. -18.25 m/s2

D. -11 m/s2—

 

 

3. An object has a mass of 180 kg on the moon. What is the force of gravity acting on the

object on the moon?

A. 1,764 N

B. 294 N

C. 10,584 N

D. 684 N—

 

1. In a practical machine, the power output is _______ the power input.

A. smaller than

B. larger than

C. equal to

D. multiplied by

 

 

2. If a stone falls past a bird on a ledge moving at 4 m/s, how fast will the stone be moving

just before it hits the ground below 9 seconds later?

A. 92.2 m/s

B. 48.2 m/s

C. 352.8 m/s

D. 36 m/s

 

 

3. The ratio of output power to input power, in percent, is called

A. conductivity.

B. efficiency.

C. work.

D. horsepower.