Mechanical Comprehension · Practice test 3

Question 1Not answered

A loading ramp is 15 feet long and rises 3 feet. What is its mechanical advantage?

1. 18
2. 45
3. 0.2
4. 5

Question 2Not answered

A pulley system has 3 rope segments supporting the moving load. What is its ideal mechanical advantage?

1. 3
2. 6
3. 1.5
4. 1

Question 3Not answered

An axe blade splitting a log is best described as an example of which simple machine?

1. a lever
2. a screw
3. a wedge
4. a wheel and axle

Question 4Not answered

A rack and pinion arrangement converts

1. straight-line motion into heat
2. rotary motion into straight-line motion
3. high speed into high torque only
4. motion between two parallel shafts

Question 5Not answered

A rocket expels exhaust gas downward and rises upward. This best illustrates

1. Newton's first law
2. Newton's third law
3. the conservation of mass
4. Pascal's principle

Question 6Not answered

A drive gear with 40 teeth turns a driven gear with 10 teeth. If the drive gear turns at 100 rpm, how fast does the driven gear turn?

1. 25 rpm
2. 100 rpm
3. 40 rpm
4. 400 rpm

Question 7Not answered

A doorknob is an example of which simple machine?

1. A wheel and axle
2. A pulley
3. A wedge
4. An inclined plane

Question 8Not answered

Adding a second movable pulley to a lifting system will

1. increase the mechanical advantage
2. decrease the mechanical advantage
3. leave the mechanical advantage unchanged
4. reverse the direction of the pull

Question 9Not answered

Two forces act on a crate along the same line: 30 newtons to the right and 20 newtons to the left. What is the net force?

1. 50 newtons to the right
2. 10 newtons to the right
3. 10 newtons to the left
4. 600 newtons to the right

Question 10Not answered

Which of Newton's laws best explains why a passenger's body keeps moving forward when the car halts abruptly?

1. the second law, force equals mass times acceleration
2. the third law, action and reaction
3. the law of conservation of momentum only
4. the first law, inertia

Question 11Not answered

A wedge with a long, gradual taper compared to a wedge with a short, steep taper will generally

1. provide less mechanical advantage
2. provide the same mechanical advantage regardless of shape
3. only work when driven in sideways
4. provide greater mechanical advantage but require more distance to drive in

Question 12Not answered

Two setups lift the same 100 newton load: Setup A uses a single fixed pulley, Setup B uses a single movable pulley. Which setup requires less effort force?

1. Setup A, the fixed pulley
2. Setup B, the movable pulley
3. both require exactly the same effort
4. neither can lift the load without a motor

Question 13Not answered

An object possesses kinetic energy on account of its

1. position
2. temperature
3. motion
4. shape

Question 14Not answered

In a first-class lever, the fulcrum sits

1. at one end with the load in the middle
2. between the effort and the load
3. at one end with the effort in the middle
4. directly under the point of effort

Question 15Not answered

Two identical carts collide head-on at equal speeds and stick together. What happens to their combined momentum after the collision?

1. it doubles
2. it is unchanged in each cart separately
3. it is zero, since the momenta cancel
4. it becomes infinite at the instant of impact

Question 16Not answered

The purpose of a block and tackle is to

1. increase the speed the load is lifted
2. remove friction from the lifting rope
3. multiply the force applied to a load
4. reduce the total work needed to lift

Question 17Not answered

A seesaw is balanced with a 40 kilogram child sitting 2 metres from the fulcrum. Where must a 20 kilogram child sit on the other side to balance it?

1. 2 metres from the fulcrum
2. 1 metre from the fulcrum
3. 8 metres from the fulcrum
4. 4 metres from the fulcrum

Question 18Not answered

An 80 pound child sits 4 feet from the centre of a seesaw. How far from the centre must a 64 pound child sit to balance it?

1. 3.2 feet
2. 4 feet
3. 5 feet
4. 6 feet

Question 19Not answered

Placing a heavier load on a sliding object increases the friction because

1. the surfaces are pressed together more firmly
2. the contact area grows with the weight
3. the object moves more slowly under load
4. heavier objects are always rougher

Question 20Not answered

A screw is best understood as

1. a lever bent into a spiral shape
2. an inclined plane wrapped around a cylinder
3. a wheel and axle with a pointed end
4. a wedge with a flattened head

Question 21Not answered

What force is needed to accelerate a 10 kilogram object at 3 metres per second squared?

1. 13 newtons
2. 3.3 newtons
3. 30 newtons
4. 90 newtons

Question 22Not answered

Under Pascal's principle, pressure applied to a fluid held in a closed system

1. is transmitted equally throughout the fluid
2. is strongest nearest the point of application
3. decreases with distance from the piston
4. acts only in the direction it was applied

Question 23Not answered

A gearbox gives a 5 to 1 reduction. With 100 pound-feet of input torque, the output torque is about

1. 20 pound-feet
2. 500 pound-feet
3. 100 pound-feet
4. 105 pound-feet

Question 24Not answered

An inclined plane makes a load easier to raise because it

1. reduces the total work needed to raise the load
2. reduces the weight of the load being moved
3. removes the effect of gravity on the load
4. reduces the force needed, spread over a longer distance

Question 25Not answered

The water pressure at a point inside a tank depends chiefly on

1. the total volume the tank holds
2. the width of the tank at that point
3. the material the tank is made from
4. the depth below the surface