CBST CBST Mechanical Reasoning 2

Question 1

A ramp 10 feet long raises a load 2 feet high. What is the mechanical advantage of this inclined plane?

Accepted Answer

5

Answer

The mechanical advantage of an inclined plane is the length divided by the height: 10 ÷ 2 = 5.

Question 2

An electric motor draws 10 amps at 120 volts. What is its power consumption?

Accepted Answer

1,200 watts

Answer

Power (watts) = Voltage × Current = 120 × 10 = 1,200 watts.

Question 3

If a spring is compressed to half its natural length, what happens to the elastic potential energy stored?

Accepted Answer

It quadruples

Answer

Elastic potential energy = ½kx², so doubling the compression (from half to full) quadruples the energy stored.

Question 4

A flat-head screwdriver is being used as a pry bar. What simple machine principle does this represent?

Accepted Answer

A lever

Answer

When used as a pry bar, the screwdriver acts as a lever with the edge of the object serving as the fulcrum.

Question 5

Which of the following best explains why a thermostat uses a bimetallic strip?

Accepted Answer

Different metals expand at different rates when heated

Answer

A bimetallic strip bends when heated because the two bonded metals have different coefficients of thermal expansion.

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