Physics word problem!?

Question

A car moving with a constant acceleration covers the distance between two points 60 m apart in 6.0 s. Its velocity as it passes the second point is 15 m/s. How far behind the first point was the car at rest?

constant acceleration = 1.67 m/s^2
The first point was passed at 5 m/s

Answer 1

The two equations you need are:

Vf = Vi + A x T
D = Vi x T + (1/2) x A x T^2

These are the equations for constant acceleration.

The first give the final velocity in terms of the initial velocity, the acceleration, and the time.

The second gives the distance travelled in terms of the initial velocity, acceleration, and time.

You can begin with the distance equation to get the velocity at the first point since you know the distance, the acceleration, and the time.

That velocity value is actually the "final" velocity of the period between the time the car started and the time it reached the first point. When the car was at rest, its velocity was 0 so you can use the velocity equation to get the time from the rest position to the first point.

Now you have the time to the first point, the acceleration, and the initial velocity (i.e. 0) so you can compute the distance you want with the distance equation.