Mechanical Comprehension · Practice test 5

Question 1Not answered

Two gears meshed directly together turn

1. in the same direction
2. in opposite directions
3. at the same speed always
4. in the same direction if sizes match

Question 2Not answered

Hydraulic systems use liquid rather than air because liquids

1. weigh less than an equal volume of air
2. barely compress, so motion transfers precisely
3. can reach much higher temperatures safely
4. flow through narrow passages more freely

Question 3Not answered

A steel cable holding up a suspended sign is primarily under which type of stress?

1. tension
2. compression
3. shear
4. no stress, cables cannot carry load

Question 4Not answered

When a small gear drives a much larger one, the output has

1. more speed and less torque
2. more of both torque and speed
3. less of both torque and speed
4. more torque and less speed

Question 5Not answered

A boat's engine pushes it east with 300 newtons while a current pushes it north with 400 newtons. What is the magnitude of the resultant force?

1. 700 newtons
2. 350 newtons
3. 100 newtons
4. 500 newtons

Question 6Not answered

A ball on a string is swung in a horizontal circle at increasing speed. What happens to the centripetal force needed to keep it moving in that circle?

1. it decreases as the speed increases
2. it stays exactly the same regardless of speed
3. it increases as the speed increases
4. it becomes zero once the ball is moving

Question 7Not answered

A garden hose has a flow rate of 20 litres per minute through an opening of 4 square centimetres. If a nozzle narrows the opening to 2 square centimetres, what happens to the water's exit speed?

1. it is cut in half
2. it approximately doubles
3. it stays the same
4. it quadruples

Question 8Not answered

If a roller coaster car's speed doubles, its kinetic energy

1. quadruples
2. doubles
3. stays the same
4. is cut in half

Question 9Not answered

A support column holding up a roof is primarily under which type of stress?

1. tension
2. compression
3. shear
4. torsion only

Question 10Not answered

A block and tackle system has a moving pulley supported by 2 strands attached to a second moving pulley supported by 2 more strands, for a total of 4 supporting strands. Ignoring friction, how much effort is needed to lift a 320 newton load?

1. 80 newtons
2. 160 newtons
3. 320 newtons
4. 40 newtons

Question 11Not answered

A book lies still on a table. The forces acting on it are

1. its weight downward only, with nothing opposing it
2. the table pushing up with a greater force than the weight
3. its weight downward and the table pushing up, equal in size
4. no forces at all, because nothing is moving

Question 12Not answered

Bearings reduce friction in a shaft by

1. increasing the area of contact
2. cooling the shaft as it turns
3. tightening the fit around the shaft
4. replacing sliding contact with rolling contact

Question 13Not answered

A first-class lever has an effort arm of 8 metres and a load arm of 2 metres. What is its mechanical advantage?

1. 4
2. 0.25
3. 16
4. 10

Question 14Not answered

A single fixed pulley provides a mechanical advantage of

1. 2
2. 0.5
3. 4
4. 1

Question 15Not answered

A balanced first-class lever has a 60 kilogram load sitting 1.5 metres from the fulcrum. What force must be applied 3 metres from the fulcrum on the other side to balance it?

1. 120 kilograms
2. 60 kilograms
3. 15 kilograms
4. 30 kilograms

Question 16Not answered

Ignoring air resistance, a heavy ball and a light ball dropped together from the same height will

1. reach the ground at the same moment
2. see the heavy one land noticeably first
3. see the light one land noticeably first
4. fall at rates depending on their shapes

Question 17Not answered

Why is the mechanical efficiency of a real gearbox always less than 100 percent?

1. gears always increase the total energy in a system
2. some input energy is lost to friction and heat
3. efficiency only applies to hydraulic systems
4. output work is always larger than input work

Question 18Not answered

A pendulum swings from a high point on one side to a high point on the other, ignoring air resistance. What happens to its total mechanical energy?

1. it steadily increases
2. it stays constant, converting between kinetic and potential
3. it is used up entirely at the bottom of the swing
4. it doubles at the highest points

Question 19Not answered

A pinion gear with 10 teeth moves along a rack. For every full turn of the pinion, if each tooth advances the rack by 2 centimetres, how far does the rack travel?

1. 10 centimetres
2. 20 centimetres
3. 5 centimetres
4. 2 centimetres

Question 20Not answered

A spring is stretched 4 centimetres by a 20 newton force. According to Hooke's law, how far will it stretch under a 40 newton force, assuming it stays within its elastic limit?

1. 2 centimetres
2. 8 centimetres
3. 4 centimetres
4. 16 centimetres

Question 21Not answered

A pulley system with a mechanical advantage of 4 raises a load 3 feet. How much rope must be pulled through?

1. 3 feet
2. 0.75 feet
3. 7 feet
4. 12 feet

Question 22Not answered

In the same hydraulic system, when the small piston moves down 10 centimetres, how far does the large piston move, given the areas are 5 and 50 square centimetres?

1. 10 centimetres
2. 1 centimetre
3. 100 centimetres
4. 50 centimetres

Question 23Not answered

Two forces act on a point at right angles: 8 newtons north and 6 newtons east. What is the resultant force?

1. 14 newtons
2. 2 newtons
3. 48 newtons
4. 10 newtons

Question 24Not answered

A worm gear drive is chosen mainly because it

1. gives the highest possible output speed for its size
2. gives a large speed reduction and usually cannot be driven backwards
3. transmits power with almost no friction losses
4. keeps the input and output shafts in line

Question 25Not answered

A skier at the top of a hill has 4000 joules of potential energy and no kinetic energy. Ignoring friction, how much kinetic energy will she have at the bottom, where potential energy is zero?

1. 0 joules
2. 2000 joules
3. 4000 joules
4. 8000 joules