Question

a 10 kg block is attached to a light chord that is wrapped around the pulley of an electric motor. at what rate is the motor doing work when it is pulling the block upward w an instantaneous speed of 3 m/s and an upward acc of 2 m/s^2?

Answer 1

Answer:

The rate of work is 360 W

Explanation:

Given:

Speed of block $v = 3 \frac{m}{s}$

Upward acceleration of block $a = 2 \frac{m}{s^{2} }$

Mass of block $m = 10$ kg

First Find the force act on block due to gravity

  $F = M (a + g)$

Where $g = 10 \frac{m}{s^{2} }$

  $F = 10 \times (10+2)$

  $F = 120$ N

For finding at what rate motor doing work when it is pulling the block upward,

  $P = F.v$

  $P = 120 \times 3$

  $P = 360$ W

Therefore, the rate of work is 360 W