Question

A truck os moving at 42 m/s when the driver sees a deer in the road ahead and slams on his breaks. How far does the truck go if it takes the truck 3.5 seconds to come to a complete stop and the maximum breaking acceleration is -12 m/s^2​

Answer 1

73.5 m

Step-by-step explanation:

Simplest way:

Average speed is (42 -0)/2 = 21 m/s for 3.5 seconds = 73.5 m

or

df = do + vo t + 1/2 a t^2

= 0 + 42 (3.5) + 1/2(-12)(3.5^2) = 73.5 m