Bennett Mechanical Test Bennett Mechanical Work and Energy Questions and Answers

Question 1

A 20 N force pushes a box 5 meters in the direction of the force. How much work is done?

Accepted Answer

100 J

Answer

Work equals force multiplied by distance (W = F × d = 20 × 5 = 100 J).

Question 2

Which unit is used to measure energy in the SI system?

Accepted Answer

Joule

Answer

The joule (J) is the SI unit of energy, equal to one newton-meter.

Question 3

A spring with a spring constant of 200 N/m is compressed by 0.1 m. What is the elastic potential energy stored?

Accepted Answer

1 J

Answer

Elastic PE = ½kx² = ½ × 200 × (0.1)² = 1 J.

Question 4

A 5 kg object is lifted to a height of 10 m. What is its gravitational potential energy? (g = 10 m/s²)

Accepted Answer

500 J

Answer

Gravitational PE = mgh = 5 × 10 × 10 = 500 J.

Question 5

A machine is 80% efficient and receives 500 J of input energy. How much useful output energy does it deliver?

Accepted Answer

400 J

Answer

Useful output = efficiency × input = 0.80 × 500 = 400 J.

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