Question

1. A weight lifter lifts a 350-N set of weights from ground level to a position over his head, a vertical distance of 2.00 m. How much work does the weight lifter do, assuming he moves the weights at constant speed?

Answer 1

To calculate the work done by the weight lifter in lifting the weights, we can use the formula:

Work = Force × Distance × cosθ

where:

• Force is the applied force in the direction of displacement,
• Distance is the displacement,
• θ is the angle between the force and the direction of displacement.

In this case, the weight lifter is moving the weights vertically upward, so the angle θ between the force applied by the weight lifter and the direction of displacement is 0 degrees (cos 0 = 1).

Given: Force = 350 N Distance = 2.00 m θ = 0 degrees

Plugging these values into the formula:

Work = 350 N × 2.00 m × cos 0 = 350 N × 2.00 m × 1 = 700 J

Therefore, the weight lifter does 700 joules (J) of work in lifting the weights.