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A student in weight lifting class lifts 65 kg from the floor to a height of 1.6 m. It takes 5.0 seconds to do the work. How much power is needed, in watts?

A. 832 W
B. 520 W
C. 203 W
D. 169 W

1 Answer

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Final answer:

The power required for lifting a 65 kg weight to a height of 1.6 m in 5 seconds is calculated using the formula P = W/t, where W is obtained using W = mgh. The final power is found to be approximately 203.84 watts, which corresponds to option C. 203 W.

Step-by-step explanation:

The question asks us to calculate the power needed for a weight lifter to lift a mass of 65 kg to a height of 1.6 m in 5.0 seconds. Power is defined as the rate at which work is done. The formula for power is P = W/t, where P is power in watts, W is work in joules (J), and t is time in seconds (s).

To find the work done (W), we use the formula W = mgh, where m is mass in kilograms, g is the acceleration due to gravity (9.8 m/s2), and h is the height in meters. The work done in lifting the 65 kg weight is therefore:

W = (65 kg)(9.8 m/s2)(1.6 m)

W = 1019.2 J

To calculate the power needed, we divide the work by the time it takes to do the work:

P = 1019.2 J / 5.0 s = 203.84 W

Therefore, the power needed is approximately 203.84 watts, which allows us to select option C. 203 W as the correct answer.

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