Olympic lifting

Question

In the 2016 Olympic games, Deng Wei set a women's record of 147 kg in the clean and jerk.

Suppose that she lifted 131 kg during practice. How much work 𝑊� did she do on the weights to lift them above her head, a distance of approximately 1.60 m? For simplicity, assume that she lifted the weights at constant speed.

Answer 1

To calculate the work Deng Wei did on the weights to lift them, we can use the formula:

work = force x distance x cos(theta)

where force is the lifting force, distance is the distance the weight is lifted, and theta is the angle between the force and the direction of motion (which is 0 degrees in this case since the weight is lifted straight up).

First, we need to convert the weight lifted from kilograms to newtons. We can do this by multiplying the weight in kilograms by the acceleration due to gravity (g), which is approximately 9.8 m/s^2:

lifting force = 147 kg * 9.8 m/s^2 = 1440.6 N

Next, we can calculate the work done during the lift:

work = lifting force x distance x cos(theta)

Plugging in the values, we get:

work = 1440.6 N x 1.60 m x cos(0) = 2304.96 J

Therefore, Deng Wei did approximately 2304.96 J of work on the weights to lift them above her head.

For the practice lift of 131 kg, we can repeat the same steps using the weight lifted in newtons:

lifting force = 131 kg * 9.8 m/s^2 = 1283.8 N

work = lifting force x distance x cos(theta)

work = 1283.8 N x 1.60 m x cos(0) = 2054.08 J

Therefore, Deng Wei did approximately 2054.08 J of work on the weights during her practice lift.