Saturday
October 25, 2014

Homework Help: Physical Science

Posted by Lizzy on Monday, September 26, 2011 at 2:17pm.

1. In which of the following units is acceleration expressed?
*A. Newtons
B. Foot-pounds
C. Kilograms
D. Meters per second squared

2. A stone falls from a ledge and takes 16 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 *C. 156.8 meters
B. 313.6 meters D. 78.4 meters

3. A tank with a flat bottom is filled with water to a height of 3.5 meters. What is the pressure
at any point at the bottom of the tank? (You can ignore atmospheric pressure when calculating
your answer.)
A. 3.5 kPa *C. 34.3 kPa
B. 3,500 kPa D. 34,300 kPa

4. The ability of a material to transfer heat or electric current is called
*A. insulation. C. conductivity.
B. porosity. D. convection.

5. 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. 5,362.56 N C. 6,700.56 N
*B. 6,150.64 N D. 7,600.18 N

6. When an automotive battery is fully charged, the sulfuric acid and water mixture will have
a specific gravity of about
A. 0.15. *C. 1.3.
B. 1.0. D. 2.5.

7. If an object weighs 39.2 N on Earth, what is its mass?
*A. 8 N C. 4 kg
B. 384.16 kg D. 78.4 N

8. If a small-diameter open glass tube is partially immersed in a vessel containing mercury,
the surface of the mercury inside the tube will be
A. lower than the mercury in the vessel, and shaped like the outside of an umbrella.
B. higher than the mercury in the vessel, and shaped like the outside of an umbrella.
C. lower than the mercury in the vessel, and shaped like the inside of a bowl.
*D. higher than the mercury in the vessel, and shaped like the inside of a bowl.

9. 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 C. 2.72 hours
*B. 3.27 hours D. 0.31 hours

10. 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 C. 360 watts
B. 43.96 watts *D. 3,640 watts

11. 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 *C. 17.2 J
B. 22.8 J D. 7.1 J

12. If a gas has a gage pressure of 206 kPa, its absolute pressure is approximately
*A. 2,060 kPa. C. 106 kPa.
B. 306 kPa. D. 20.6 kPa.

13. 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.

14. 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 C. 32 meters
B. 80 meters *D. 16 meters

15. What force is required to accelerate a body with a mass of 18 kilograms at a rate
of 36 m/s2?
*A. 2 N C. 648 N
B. 54 N D. 6,350 N

16. Oil flows upward in the wick of a lantern because of the liquid property called
A. viscosity. *C. meniscusity.
B. capillarity. D. density.

17. 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 C. 60 km/hour
*B. 36 km/hour D. 960 km/hour

18. Which of the following is the term used to describe a body’s resistance to a change in
motion?
*A. Inertia C. Gravity
B. Acceleration D. Mass

19. 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 C. -18.25 m/s2
B. -1.92 m/s2 *D. -11 m/s2

20. 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 *C. 10,584 N
B. 294 N D. 684 N

21. In a practical machine, the power output is _______ the power input.
*A. smaller than C. equal to
B. larger than D. multiplied by

22. 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 C. 352.8 m/s
B. 48.2 m/s D. 36 m/s

23. The ratio of output power to input power, in percent, is called
A. conductivity. C. work.
B. efficiency. *D. horsepower.

24. An object with a mass of 21 kilograms is lifted through a distance of 7 meters. How much
work is done?
A. 147 J C. 1,440.6 J
*B. 29.4 J D. 823.2 J

25. A car with a mass of 2,000 kilograms is moving around a circular curve at a uniform velocity
of 25 meters per second. The curve has a radius of 80 meters. What is the centripetal force
on the car?
A. 625 N C. 15,625 N
B. 703 N *D. 20,250 N

Please check my answers. They have stars by them. Thank you!

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