Question

Check the box if the object in the situation shows a change in velocity a.a dog chasing after a speeding car b.a motorcyclist applying the brakes in a speeding bike car bus turning on a traffic circle d.a bus moving at a constant speed on a straight speed

Answer 1

When driver applies brakes and the car covers distance x before coming to rest, under the effect of retarding force F.
Then
2
1
​
mv
2
=Fx
or x=
2F
mv
2

​

But when he takes turn, then
r
mv
2

​
=F
⇒r=
F
mv
2

​

It is clear that x=
2
r
​

i.e., by the same retarding force the car can be stopped in a less distance if the driver apply brakes. This retarding force is actually a friction force.