Assignment:
Part 1
1. Science greatly advanced when Galileo favored
(a) philosophical discussions over experiment.
(b) experiment over philosophical discussions.
(c) nonmathematical thinking.
(d) imagination.
2. According to Galileo, inertia is a
(a) force like any other force.
(b) special kind of force.
(c) property of all matter.
(d) concept opposite to force.
3. If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in
(a) a curved path.
(b) an outward spiral path.
(c) an inward spiral path.
(d) a straight-line path.
4. When a 10-kg block is simultaneously pushed eastward with a force of 20 N and westward with a force of 15 N, the combination of these forces on the block is
(a) 35 N west.
(b) 35 N east.
(c) 5 N east.
(d) 5 N west.
5. The equilibrium rule, _F = 0, applies to
(a) objects or systems at rest.
(b) objects or systems in uniform motion in a straight line.
(c) both of these
(d) neither of these
6. When you stand on two bathroom scales, one foot on each scale with weight evenly distributed, each scale will read
(a) your weight.
(b) half your weight.
(c) zero.
(d) actually more than your weight.
7. Your average speed in skateboarding to your friend's house is 5 m/s. It is possible that your instantaneous speed at some point was
(a) less than 5 m/s.
(b) 5 m/s.
(c) more than 5 m/s.
(d) any of these
8. During each second of free fall, the speed of an object
(a) increases by the same amount.
(b) changes by increasing amounts.
(c) remains constant.
(d) doubles.
9. If a falling object gains 10 m/s each second it falls, its acceleration is
(a) 10 m/s.
(b) 10 m/s per second.
(c) both of these
(d) neither of these
10. A freely falling object has a speed of 30 m/s at one instant. Exactly 1 s later its speed will be
(a) the same.
(b) 35 m/s.
(c) more than 35 m/s.
(d) 60 m/s.
Part 2
Choose the BEST answer to each of the following.
1. If gravity between Earth and an orbiting communications satellite suddenly vanished, the satellite would move in
(a) a curved path.
(b) a straight-line path.
(c) a path directed toward Earth's surface.
(d) an outward spiral path.
2. If an object moves along a curved path, then it must be
(a) accelerating.
(b) acted on by a force.
(c) both of these
(d) none of these
3. A ball rolls down a curved ramp as shown. As its speed increases, its rate of gaining speed
(a) increases.
(b) decreases.
(c) remains unchanged.
(d) none of these
4. The reason a 10-kg rock falls no faster than a 5-kg rock in free fall is that the
(a) 10-kg rock has greater acceleration.
(b) 5-kg rock has greater acceleration.
(c) force of gravity is the same for both.
(d) force/mass ratio is the same for both.
5. As mass is added to a pushed object, its acceleration
(a) increases.
(b) decreases.
(c) remains constant.
(d) quickly reaches zero.
6. The amount of air resistance that acts on a wingsuit flyer (and a flying squirrel) depends on the flyer's
(a) area.
(b) speed.
(c) area and speed.
(d) acceleration.
7. You drop a soccer ball off the edge of the administration building on your campus. While the soccer ball falls, its speed
(a) and acceleration both increase.
(b) increases and its acceleration decreases.
(c) and acceleration both decrease.
(d) decreases and its acceleration increases.
8. The amount of force with which a boxer's punch lands depends on the
(a) physical condition of the boxer.
(b) mass of what's being hit.
(c) boxer's attitude.
(d) none of these
9. When the neck of an air-filled balloon is untied and air escapes, the balloon shoots through the air. The force that propels the balloon is provided by the
(a) surrounding air.
(b) ejected air.
(c) air still in the balloon.
(d) ground beneath the balloon.
10. The force that propels a rocket is provided by
(a) gravity.
(b) Newton's laws of motion.
(c) its exhaust gases.
(d) the atmosphere against which the rocket pushes.
Part 3
Choose the BEST answer to each of the following
1. A 1-kg ball has the same speed as a 10-kg ball. Compared with the 1-kg ball, the 10-kg ball has
(a) less momentum.
(b) the same momentum.
(c) 10 times as much momentum.
(d) 100 times as much momentum.
2. In the absence of external forces, momentum is conserved in
(a) an elastic collision.
(b) an inelastic collision.
(c) either an elastic or an inelastic collision.
(d) neither an elastic nor an inelastic collision.
3. If the running speed of Fast Freda doubles, what also doubles is her
(a) momentum.
(b) kinetic energy.
(c) both of these
(d) neither of these
4. Which of these equations best explains the usefulness of automobile airbags?
(a) F = ma
(b) Ft = _(mv)
(c) KE = 12 mv2
(d) Fd = _ 12 mv2
5. Which of these equations is most useful for solving a problem that asks for the distance a fast-moving box slides across a post office floor and comes to a stop?
(a) F = ma
(b) Ft = _(mv)
(c) KE = 12 mv2
(d) Fd = _ 12 mv2
6. How much work is done on a 200-kg crate that is hoisted 2 m in a time of 4 s?
(a) 400 J
(b) 1000 J
(c) 1600 J
(d) 4000 J
7. A model airplane moves twice as fast as another identical model airplane. Compared to the kinetic energy of the slower airplane, the kinetic energy of the faster airplane is
(a) the same.
(b) twice as much.
(c) four times as much.
(d) more than four times as much.
8. The ultimate source of energy for wind power, fossil fuels, and biomass is
(a) nuclear.
(b) matter itself.
(c) solar.
(d) photovoltaic.
9. A billiard ball and a bowling ball have the same speed. Compared with the heavier bowling ball, the lighter billiard ball has
(a) less momentum and less kinetic energy.
(b) the same momentum and same kinetic energy.
(c) more momentum but less kinetic energy.
(d) less momentum but more kinetic energy.
10. A machine cannot multiply
(a) forces.
(b) distances.
(c) energy.
(d) but it can multiply all of these.