# A machine that uses 200 watts of power moves an object a distance of 15 meters in 25 seconds. What is the force needed and the work done by this machine?

Dec 8, 2015

(a)

$333.3 \text{N}$

(b)

$5 \text{kJ}$

#### Explanation:

(a)

Power is the rate of doing work.

$P = \frac{W}{t}$

$\therefore W = P \times t$

Work done is force x distance moved in direction of force.

$W = F \times d$

$\therefore F \times d = P \times t$

$\therefore F = \frac{P \times t}{d} = \frac{200 \times 25}{15} = 333.3 \text{N}$

(b)

Since $W = F \times d$

$W = 333.3 \times 15 = 5000 \text{J"=5"kJ}$