Answer:
The work done by friction was [tex]-4.5\times10^{5}\ J[/tex]
Explanation:
Given that,
Mass of car = 1000 kg
Initial speed of car =108 km/h =30 m/s
When the car is stop by brakes.
Then, final speed of car will be zero.
We need to calculate the work done by friction
Using formula of work done
[tex]W=\Delta KE[/tex]
[tex]W=K.E_{f}-K.E_{i}[/tex]
[tex]W=\dfrac{1}{2}mv_{f}^2-\dfrac{1}{2}mv_{f}^2[/tex]
Put the value of m and v
[tex]W=0-\dfrac{1}{2}\times1000\times(30)^2[/tex]
[tex]W=-450000 \ J[/tex]
[tex]W=-4.5\times10^{5}\ J[/tex]
Hence, The work done by friction was [tex]-4.5\times10^{5}\ J[/tex]
