Question

Brenda and Taylor push their car into the driveway because it will not start .The car ha a mass of 850 kg. They apply a force of 800 N for 30 seconds to move the car 15 m. (Use correct units in all answers.)
a. How much work do they perform?

b. What is their power?

Answer 1

Explanation:

Given that,

Mass of the car, m = 850 kg

Force applied, F = 800 N

Time, t = 30 s

Distance covered, d = 15 m

To find,

(a) work done

(b) Power

Solution,

(a) Let W is the work done. The product of force and displacement is called work done. Its expression is given by :

$W=F\times d$

$W=800\ N\times 15\ m$

W = 12000 J

(b) The work done divided by time taken is called power of an object. It is given by :

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

$P=\dfrac{12000\ J}{30\ s}$

P = 400 W

Answer 2

a) W=F*d=800*15=12000 J

b) P=W/t=12000/30=400 W