Physics: Constant Acceleration4?

Question

You are driving your new sports car t a velocity of 90km/h when you suddenly see a dog step into the road 50m head. You hit the brakes hard to get the maximum deceleration of 7.5m/second squared. How far will you go before stopping? Can you avoid hitting the dog?

Please help me.. Thanks! ♥

Answer 1

90km/h = 90,000m/3600 s = 25 m/s

v=v0+at

0=25-7.5t   7.5t=25    t=25/7.5  t=3.333 seconds

x=x0+v-t+0.5at^2

x=0+25(3.333) -3.75(3.333^2) = 41.663meters

The Dog is safe!

Astrobuf