Question

A car and a truck move on the road in the same direction at the same

speed. Both vehicles slow down with the same stopping force.
Which statement best explains why the truck needs to more time to stop?

Answer 1

The statements are not given, so I will answer in a general way.

We know that when one object is moving with a velocity V, and it wants to come to stop, it needs to accelerate in the opposite direction to the initial velocity (Or decelerate).

As larger this acceleration is, the faster the object will come to a full stop.

Now we have a car (with a mass m) and a truck (with a mass M) are moving with a velocity V.

We can assume that the mass of the truck is larger than the mass of the car, then:

M > m.

Now also remember Newton's second law:

F = m*a

Force equals mass times acceleration.

And we know that both vehicles stop with the same stopping force.

Then the acceleration (deceleration actually) that experiences the car is:

a = F/m

While the acceleration that experiences the truck is:

a' = F/M

Because M is larger than m, we will have:

a' < a

Then the deceleration of the truck is smaller than the one of the car, which means that the car will come to a full stop faster than the truck (or the truck needs more time to stop)