Question

Bob is driving the getaway car after the big bank robbery. He’s going 50 m/s when hisheadlights suddenly reveal a nail strip that the cops have placed across the road 150 min front of him. If Bob can stop in time, he can throw the car into reverse and escape.But if he crosses the nail strip, all his tires will go flat and he will be caught. Bob’sreaction time before he can hit the breaks is 0.60 s, and his car’s maximum decelerationis 10 m/s2. Is Bob in jail?

Answer 1

Answer:

Bob is in jail, he couldn't escape just by 5 meters!

Explanation:

Hello

By the moment He hits the breaks he has advanced $50m/s*0.6s=30meters$ this means that he has 120 meters to stop.

After that, we need to know how much take the car to stop completely, so we use $v=v_{0}-a*t$, then $0=50m/s-10m/s^{2} *t$, if we isolate it for t we have $t=\frac{50m/s}{10m/s^{2}} =5s$

Finally we can use $x(t)=s_{0}+v_{0}*t -\frac{a*t^{2} }{2}$ and $t=5s$, so we have $x(5)=30m+50m/s *5s-\frac{10m/s^{2} *(5s)^{2} }{2}=155m$, the distance that is needed by the car to be completely stopped is greater than 150 m.