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

Answer:

Work done on the car will be 548440.9463 J

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 $=115\times \frac{5}{18}=31.943m/sec$

Work done is equal to change in kinetic energy

So work done $=\frac{1}{2}mv_f^2-\frac{1}{2}mv_i^2$

=$=\frac{1}{2}m(v_f^2-v_i^2)=\frac{1}{2}\times 1075\times (0^2-31.943^2)=-548440.946J$

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