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# 2. What is the kinetic energy of an object that has a mass

### Resolved Question:

2. What is the kinetic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s?

A. 12,000 J
B. 2,940 J
C. 6,000 J
D. 5,880 J

3. The main difference between speed and velocity involves

A. direction.
B. gravity.
C. weight.
D. distance.

4. A stone falls from a ledge and takes 8 seconds to hit the ground. The stone has an original velocity of 0 m/s. How tall is the ledge?

A. 1,254.4 meters
B. 313.6 meters
C. 78.4 meters
D. 39.2 meters

5. If a stone with an original velocity of 0 is falling from a ledge and takes 8 seconds to hit the ground, what is the final velocity of the stone?

A. 39.2 m/s
B. 78.4 m/s
C. 156.8 m/s
D. 42.6 m/s

6. If an object has a mass of 20 kg, what is the force of gravity acting on it on earth?

A. 196 N
B. 1.96 kg
C. 2.04 kg
D. 32.67 N

7. A car with a mass of 1,200 kilograms is moving around a circular curve at a uniform velocity of 20 meters per second. The centripetal force on the car is 6,000 newtons. What is the radius of the curve?

A. 160 meters
B. 16 meters
C. 32 meters
D. 80 meters

8. An object with a mass of 78 kilograms is lifted through a height of 6 meters. How much work is done?

A. 764.4 J
B. 47.75 J
C. 4,586.4 J
D. 468 J

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

A. capillarity.
B. viscosity.
C. density.
D. meniscusity.

10. The orbits of planets being elliptical was one the planetary laws developed by

A. Kepler.
B. Ptolemy.
C. Brahe.
D. Copernicus.

11. When an automotive battery is fully charged, the sulfuric acid and water mixture will have a specific gravity of about

A. 2.5.
B. 1.3.
C. 1.0.
D. 0.15.

12. A machine is supplied energy at a rate of 4,000 W and does useful work at a rate of 3,760 W. What is the efficiency of the machine?

A. 97 percent
B. 94 percent
C. 92 percent
D. 96 percent

13. A man standing on a bus remains still when the bus is at rest. When the bus moves forward and then slows down the man continues moving forward at the original speed. This is an example of the effect of

A. weight.
B. velocity.
C. inertia.
D. gravity.

14. What force is required to accelerate a body with a mass of 15 kilograms at a rate of 8 m/s²?

A. 1.875 kg
B. 23 kg
C. 23 N
D. 120 N

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

A. smaller than
B. equal to
C. multiplied by
D. larger than

16. An object has a mass of 120 kg on the moon. What is the force of gravity acting on the object on the moon?

A. 196 N
B. 1,176 N
C. 20 N
D. 12.24 N

17. The metric unit of force is the

A. nanometer.
B. kilogram.
C. gram.
D. newton.

18. The ability of a material to transfer heat or electric current is called

A. insulation.
B. convection.
C. porosity.
D. conductivity.

19. In which of the following units is acceleration expressed?

A. Meters per second squared
B. Newtons
C. Kilograms
D. Foot-pounds

20. A steel block has a volume of 0.08 m³ and a density of 7,840 kg/m³. What is the force of gravity acting on the block (the weight) in water?

A. 6,700.56 N
B. 7,600.18 N
C. 6,150.64 N
D. 5,362.56 N
Submitted: 5 years ago.
Category: Homework
Expert:  Matrix replied 5 years ago.