You need to purchase a motor to supply 400 joules [J] in 10 seconds [s]. All of the motors you can choose from are 80% efficient. What is the minimum wattage [W] on the motor you need to choose

Question

Physics

Paula Lang

16 July, 20:55

You need to purchase a motor to supply 400 joules [J] in 10 seconds [s]. All of the motors you can choose from are 80% efficient. What is the minimum wattage [W] on the motor you need to choose

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Answers (1)

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Rubi Benson · Answer 1

32 W.

Explanation:

Power: This can be defined as the ratio of energy to time. The S. I unit of power is watt (W). The formula for power is given as,

P = W/t ... Equation 1

Where P = power, W = work done, t = time.

Given: W = 400 J, t = 10 s.

Substitute into equation 1

P = 400/10

P = 40 W.

If the motors that is choose is 80% efficient,

P' = P (0.8)

Where P' = minimum power

P' = 40 (0.8)

P' = 32 W.