Physical Science (GS 103-2)

1. The proportion of the world’s electricity that comes from nuclear energy is about b.    1/6
2.    An airplane travels at constant speed for a distance of 120 km in a time of 15 min. Its speed is. c.    480 km/in
3.    The world’s fastest-growing source of clean energy is 
c. Hydropower

4.    When the sun, the earth, and the moon are all in line a.    high tides and low tides are both higher than usual
5.    If the Antarctic and Greenland icecaps melt completely, sea level will rise d.    everywhere by about 10 m
6.    A sedentary person requires about 6 million J of energy per day. This rate of energy consumption is equivalent to about a.    70 W
7.    If the earth were to resolve on its axis slower than it does today, its shape a.    would be closer to a perfect sphere
8.    A ball is thrown upward with a speed of 30 m/s. It will continue to rise about c.    3.1 s
9.     On a molecular level heat is a.    kinetic energy
10. In bright sunlight, a solar cell with an efficiency of 20% might have a power output per square meter of c.    200 W
11. On a rainy day the maximum frictional force between a car’s tires and a certain level road surface is reduced to half its usual value. The maximum safe speed for rounding a curve is  

d.    reduced to 71% of its usual value
12. To prevent it from tumbling in flight, a projectile such as a football is sent off spinning. The physical principle involved is

c.    conservation of angular momentum
13. A 1-N weight has a PE relative to the ground of 1 J when it is at a height of  b.    1 m
14.    The earth’s atmosphere is mainly heated by c.    infrared light radiated by the earth
15.    A ship travel 20 km to the south and then 40 km to the west. The ship’s displacement from its starting point is c.    45 km
16.    The speed of a 4000-kg truck whose KE is 1.8 MJ is b.    30 m/s
17.  Compact fluorescent light bulbs are more efficient than incandescent light bulbs c.    and last longer
18.    Which one or more of the following pairs of displacements cannot be added to give a resultant displacement of 2 m? d.     1 m and 4 m
19.    A horse has a power output of 1 hp (746 W) when pulling a cart. If the cart covers 100 m in 30 s, the force exerts on the cart is
a.    0.22 kN
20.    An optimistic projection for 2050 suggests that 9 billion might then be the population of d.    The world