Problema Solution
while driving on a highway, you see a black bear walk out into the road in front of your car. If you are travelling at 90km/h and the brakes can apply a -3.75 m/s acceleration to your vehicle, how long does it take you to stop?
Answer provided by our tutors
u = 90 km/h = (90*10^3)/(60^60) = 900/36 m/s is the initial velocity of the car
v = 0 the final velocity
a = -3.75 m/s^2 is the uniform acceleration
v = u + a*t
0 = 900/36 - 3.75*t
900/36 - 3.75*t = 0
by solving the equation we find
t = 6.67 seconds
click here to see the step by step solution of the equation
it takes 6.67 seconds for the car to stop.