Physical Science

1
Physical Science

• Chapter 4-5.1 Review

2

• Mechanical advantage can be defined as the ratio
  of
• a. work input to work output.
• b. work output to work input.
• c. output force to input force.
• d. input force to output force.

3

• Which of the following is NOT considered a simple
  machine?
• a. Inclined plane
• b. Electric motor
• c. Screw
• d. Rope and Pulley

4

• What two variables determine the mechanical
  advantage of a simple machine?
• speed, force  
• force, distance  
• acceleration, power  
• power, distance

5

• A screwdriver can be used to open a can of paint.
  In this situation, the screwdriver is being used
  as a  
• wheel and axle.  
• screw.  
• lever.  
• inclined plane.

6

• An oar is used to row a boat. The distance
  between the oar lock (fulcrum) and the rower's
  hand is 104 cm. This distance is considered
• the effort distance.  
• the resistance distance.  
• the mechanical advantage of the oar.  
• the effort force.

7

• The distance between the rower's hand and the
  fulcrum is 104 cm. The distance between the
  fulcrum and the water is 45.0 cm. What is the
  mechanical advantage of the oar?
• 0.433  
• 2.31  
• 3.05  
• 59.0

8

•    The mechanical advantage of another oar is
  3.00. If the resistance force of the water is
  35.0 lb, what is the effort force exerted by the
  rower?
• 11.7 lb  
• 0.0857 lb  
• 105 lb  
• 32.0 lb

9

•      The mechanical advantage for a pulley system
  is determined by
• counting the number of strands holding the
  resistance force.  
• counting the number of strands holding and not
  holding the resistance force.  
• adding the radii of the pulleys.  
• multiplying the radii of the pulleys.

10

• How much power is necessary to do 70 joules of
  work in 10 seconds?
• 1.42 Watts
• 7 Watts
• 700 Watts
• .14 Watts

11

• A block and tackle system has an input force of 5
  Newtons and an output force of 30 Newtons. What
  is the mechanical advantage of the system?
• 150
• 6
• .166
• 0

12

• A first class lever is used to a lift a 400 lb.
  load. If the input arm is 7.0 ft long, what is
  the minimum length of output arm that would allow
  the load to be lifted using only 100 lbs. of
  input force?
• 1.25 ft
• 28 ft
• 700 ft
• 14 ft

13

• On a 10-speed bicycle, gears increase the
  mechanical advantage of the bicycle. In which of
  the following situations would you want the
  greatest mechanical advantage for the gear
  system?
• a. Climbing up a hill
• b. Coasting down a hill
• c. Riding on level ground
• d. Stopping suddenly to avoid a crash

14

• A lever rotates around a fixed point called a
• a. ball bearing.
• b. gear.
• c. pulley.
• d. fulcrum.

15

• If the output force of a lever is located between
  the fulcrum and input force, the lever is a
• a. first class lever.
• b. second class lever.
• c. third class lever.
• d. Not enough information is given.

16

• A mover wants to use his own weight to lift a
  450-pound box with a lever and a fulcrum. He
  weighs 150 pounds. If the output arm is 1 meter
  long, how long does the input arm need to be?
• a. 0.3 meters
• b. 3 meters
• c. 4 meters
• d. 6 meters

17

• Gears may be combined in a system to
• a. change force.
• b. change speed.
• c. change direction.
• d. All of the above are true.

18

• Work may be measured using units of
• a. watts.
• b. newtons.
• c. joules.
• d. newtons per second.

19

• Your friend claims to have invented a perpetual
  motion machine with an efficiency of 110 percent.
  You tell him his invention is impossible because
  it violates
• a. Newton's first law of motion.
• b. Newton's second law of motion.
• c. Newton's third law of motion.
• d. the law of conservation of energy.

20

• Calculate the work needed to lift a block
  weighing 4 newtons a distance of 10 meters.
• a. 0.4 joules
• b. 2.5 joules
• c. 4 joules
• d. 40 joules

21

• The efficiency of a modern bicycle is 95 percent.
  If you exert 200 joules in pedaling a bicycle on
  level ground, what is the work output?
• a. 95 joules
• b. 105 joules
• c. 190 joules
• d. 295 joules

22

• A force applied to a machine
• Input force
• Output force
• Resistance
• distance

23

• The distance from the fulcrum to the point of the
  output force
• Fulcrum
• Output distance
• Input distance
• effort

24

• An unpowered mechanical device, such as a lever,
  that has an input and output force
• Mechanical system
• Simple machine
• Inclined plane
• prototype

25

• A wheel with teeth that is used to change
  direction and/or speed of rotating motion
• Rope and pulley
• Screw
• Gear
• Engineering cycle