In the same instant that a Porsche races past him at 130 km/h, a speed cop gets off his motorcycle, accelerates uniformly at 8 m/s^2, to catch the speedster. After 5 seconds the trafic officer reaches his top speed, which he then maintains until he reaches up to the car. How far down the road does the bike draw level with the Porsche?
2 answers
The cop should really get ON the motorcycle if he wants to catch the guy. Which he never will because his top speed is only 40 kph.
Oops. My mistake, the acc is in m/s^2.
So the porsche is going 36.1 m/s.
x = 180.5 + 36.1t (180.5 during 5 seconds)
and for the cop
x = 100 + 40t (the 100 is how far he went during the acceleration)
so 3.9t = 80.5
and add t = 20.6 + 5 =25.6
x = 25.6*36.1
So the porsche is going 36.1 m/s.
x = 180.5 + 36.1t (180.5 during 5 seconds)
and for the cop
x = 100 + 40t (the 100 is how far he went during the acceleration)
so 3.9t = 80.5
and add t = 20.6 + 5 =25.6
x = 25.6*36.1
3 answers