4) The brakes on your car can slow you at a rate of 5.2 m/s?. If you are going 137 km/h and suddenly see a state trooper, what is the minimum time in which you can get your car under the 90 km/h speed limit? (The answer reveals the futility of braking to keep your high speed from being detected with a radar or laser gun.)

Solve an example by a graphing method. On the same graph, plot position versus time for the car and the trooper. From the intersection of the two curves, read the time at which the trooper overtakes the car.

Watch out for the speed limit!

You are driving a car speed 45.0 m/s when you pass a trooper on a motorcycle hidden behind a billboard. One second after your car passes the billboard, the trooper sets out from the billboard to catch you, accelerating at a constant rate of 3.00 . How long does it take the trooper to overtake your car?

A motorist suddenly notices a stalled car ahead and slams on brakes with an acceleration of 6.3 m/s^2. Unfortunately, the car collides. Police estimate the first car was moving at 5.0 m/s at the moment of the collison. They also measure skid marks 34 meters long. Assume each car has a mass of 1500kg. The speed limit on the road was 45 miles per hour. Was the incoming car speeding (i.e before applying the brakes)?

You are driving with a velocity of 85 in a 65 speed-limit zone whenyou see a police radar unit pointing directly at you.
You put on your brakes and quickly slow down with an accelerationof -3.3 .

a)
What is your initial velocity in units?

1

b)
What is the speed limit in units?

2
c)
How much time did it take you to slow down to the speedlimit?

3 s
d)
How far did your car travel while you were slowing down to thespeed limit?

4 m