Mechanical Comprehension · Practice test 6

Question 1Not answered

A simply supported beam has a single heavy load placed exactly at its centre span between two end supports. Compared to spreading the same total load evenly along the beam, the centred point load creates

1. less bending stress overall
2. exactly the same stress distribution
3. no bending stress at all
4. greater bending stress at the centre of the beam

Question 2Not answered

A crate has a mass of 20 kilograms. What is its weight on Earth, using 10 m/s^2 for gravity?

1. 20 newtons
2. 2 newtons
3. 200 newtons
4. 2000 newtons

Question 3Not answered

A one-way check valve in a pump system is designed to

1. mix two different fluids together
2. increase fluid pressure without any moving parts
3. measure the temperature of the fluid passing through
4. allow fluid to flow in only one direction and block backflow

Question 4Not answered

An object that is denser than the fluid it is placed in will

1. float exactly at the surface
2. sink, because it cannot displace enough fluid to equal its own weight
3. always rise to the top eventually
4. neither sink nor float, remaining still anywhere

Question 5Not answered

A 12-tooth gear turning at 60 revolutions per minute drives a 24-tooth gear. How fast does the larger gear turn?

1. 30 revolutions per minute
2. 120 revolutions per minute
3. 48 revolutions per minute
4. 72 revolutions per minute

Question 6Not answered

A crowbar used to pry a nail out of a board acts as a lever of which class?

1. Second class
2. First class
3. Third class
4. It is not a lever

Question 7Not answered

A small gear with 12 teeth drives a large gear with 60 teeth. What is the gear ratio between them?

1. 1 to 5
2. 12 to 60, meaning no reduction
3. 5 to 1
4. 60 to 12, meaning the large gear spins faster

Question 8Not answered

An object is said to be in equilibrium when

1. it has come completely to rest
2. no forces are acting on it at all
3. all the forces on it cancel out
4. its weight exceeds the applied force

Question 9Not answered

A worker pulls 60 newtons on a rope threaded through a block and tackle with 4 supporting strands. What is the maximum load this can lift, ignoring friction?

1. 15 newtons
2. 64 newtons
3. 60 newtons
4. 240 newtons

Question 10Not answered

On a lever, moving the fulcrum closer to the load, while keeping the effort point fixed, will

1. decrease the mechanical advantage
2. increase the mechanical advantage
3. have no effect on mechanical advantage
4. reverse the direction of the load's motion only

Question 11Not answered

A ramp 20 feet long rises 4 feet. Ignoring friction, what force is needed to push a 500 pound load up it?

1. 500 pounds
2. 2500 pounds
3. 100 pounds
4. 125 pounds

Question 12Not answered

A force of 20 newtons acts on a 5 kilogram mass. What acceleration results?

1. 100 metres per second squared
2. 25 metres per second squared
3. 4 metres per second squared
4. 0.25 metres per second squared

Question 13Not answered

A large pulley drives a small pulley by belt. The small pulley turns

1. slower than the large one
2. at the same speed as the large one
3. faster than the large one
4. in the opposite direction to it

Question 14Not answered

Atmospheric pressure at sea level is approximately

1. 1 pound per square inch
2. 50 pounds per square inch
3. 15 pounds per square inch
4. 100 pounds per square inch

Question 15Not answered

Which pair correctly matches a simple machine with a common real-world example?

1. wheel and axle, a shovel used to pry up soil
2. screw, a seesaw
3. inclined plane, a pair of scissors
4. wedge, an axe blade

Question 16Not answered

A knife blade works as which simple machine?

1. A lever
2. A wedge
3. A pulley
4. A wheel and axle

Question 17Not answered

A bevel gear is used to

1. transmit motion between shafts that meet at an angle
2. convert rotation into straight-line motion
3. produce very large speed reductions
4. connect two shafts lying end to end

Question 18Not answered

A mechanic needs 90 pound-feet of torque. Using a wrench 3 feet long, what force must be applied at the end?

1. 270 pounds
2. 30 pounds
3. 93 pounds
4. 87 pounds

Question 19Not answered

A 5 kilogram block accelerates at 4 metres per second squared. How much net force is acting on it?

1. 1.25 newtons
2. 20 newtons
3. 9 newtons
4. 40 newtons

Question 20Not answered

A machine takes in 500 joules of energy and produces 350 joules of useful work, the rest lost as heat. What is its mechanical efficiency?

1. 70 percent
2. 35 percent
3. 143 percent
4. 50 percent

Question 21Not answered

A screw with finer threads, meaning more turns per inch, provides

1. less mechanical advantage but faster travel
2. greater mechanical advantage and faster travel
3. no change in mechanical advantage at all
4. greater mechanical advantage but slower travel

Question 22Not answered

A wheel and axle has a wheel radius of 25 centimetres and an axle radius of 5 centimetres. What is its ideal mechanical advantage?

1. 5
2. 0.2
3. 125
4. 20

Question 23Not answered

A 20-tooth gear drives a 60-tooth gear. The larger gear turns

1. one third as fast as the driver
2. three times as fast as the driver
3. at the same speed as the driver
4. one sixth as fast as the driver

Question 24Not answered

A 2 kilogram book sits on a shelf 3 metres above the floor. Using 10 m/s^2 for gravity, what is its gravitational potential energy?

1. 60 joules
2. 6 joules
3. 30 joules
4. 600 joules

Question 25Not answered

A lever has an effort arm of 8 feet and a resistance arm of 2 feet. What is its mechanical advantage?

1. 16
2. 6
3. 4
4. 0.25