A 3.00 watt electric motor is plugged into an electrical outlet It takes the motor 30 00 seconds to lift a mass of 254.9 g a distance of

10.00 cm. In that time, the motor has used 90.00 J of energy Assuming no energy leaves the system, how much heat has been

added to the system by the end of those 30 seconds?

Question

Rachael Kirby

Physics

13 April, 08:19

A 3.00 watt electric motor is plugged into an electrical outlet It takes the motor 30 00 seconds to lift a mass of 254.9 g a distance of

10.00 cm. In that time, the motor has used 90.00 J of energy Assuming no energy leaves the system, how much heat has been

added to the system by the end of those 30 seconds?

+2

Answers (1)

Know the Answer?

Elliana · Answer 1

89.75 J

Explanation:

The motor uses 90.00 J of electrical energy. Any of that energy that isn't used to do work is converted to heat.

The amount of work done is:

W = mgh

W = (0.2549 kg) (9.81 m/s²) (0.1000 m)

W = 0.2501 J

So the heat generated is:

Q = 90.00 J - 0.2501 J

Q = 89.75 J