Question

The work done to increase the velocity of a car of 800kg from 5m/sec to 10m/sec

Answer 1

check the attachment

Answer 2

Answer:

30 kJ

Explanation:

Given:

• m = mass of the car = 800 kg

• u = initial velocity of the car = 5 m/s

• v = final velocity of the ball = 10 m/s

Assume:

• W = work done to increase the velocity

The work-energy theorem says that work done by various forces acting on an object causes a change in kinetic energy of the object which is equal to the total work done. This means the work done to increase the velocity of the car will be equal to the change in kinetic energy of the car.

$\therefore W = \dfrac{1}{2}m(v^2-u^2)\\\Rightarrow W = \dfrac{1}{2}\times 800\times (10^2-5^2)\\\Rightarrow W = \dfrac{1}{2}\times 800\times75\\\Rightarrow W = 30000\ J\\\Rightarrow W = 30\ kJ$

Hence, the required work done is 30 kJ.