Question

How much work must be done to stop a 1075-kg car traveling at 115 km/h ? Express your answer to two significant figures and include the appropriate units

Answer 1

Work done on the car will be 548440.9463 J

Step-by-step explanation:

We have given mass of the car m = 1075 kg

As the car finally stops so final velocity of the car
`v_f=0m/sec`

Initial velocity of car u = 115 km/hr
`=115* (5)/(18)=31.943m/sec`

Work done is equal to change in kinetic energy

So work done
`=(1)/(2)mv_f^2-(1)/(2)mv_i^2`

=
`=(1)/(2)m(v_f^2-v_i^2)=(1)/(2)* 1075* (0^2-31.943^2)=-548440.946J`

As the work done is negative so work is done on the car to stop it .