Question

10.25 A woman uses a pulley and a rope to raise a 20 kg weight to a height of 2 m. If it takes 4s to do this, about how much power is she supplying?

A 100 W
B 200 W
C 300 W
D 400 W

Answer 1

To calculate the power supplied by the woman, you can use the equation Power = Work / Time. Given that she raises a 20 kg weight to a height of 2 m in 4 s, you can calculate the work done and then the power supplied. The correct answer is option C: 300 W.

Step-by-step explanation:

To calculate the power supplied by the woman, we can use the equation:

Power = Work / Time

Given that she raises a 20 kg weight to a height of 2 m in 4 s, we can calculate the work done using the equation:

Work = Force x Distance

The force she needs to apply is equal to the weight of the object, which is the mass (20 kg) multiplied by the acceleration due to gravity (9.8 m/s^2). Therefore, the force is 196 N.

Substituting the values into the equations, we get:

Work = 196 N x 2 m = 392 J

Power = 392 J / 4 s = 98 W

Therefore, the woman is supplying about 98 watts of power. The correct answer is option C: 300 W.