Question

a car starts from rest and travels for 8 seconds with a uniform acceleration of 2.9 m/s^2. the driver then applies the brakes causing a uniform acceleration of -1.7m/s^2. if the brakes are applied for 2.7s how fast is the car going at the end of the braking period?

Answer 1

a₁=2.9 m/s^2 t₁=8 s

v₁=a₁*t₁= 2.9*8 m/s

a₂=-1.7 m/s^2 t₂=2.7 s

v₂=v₁-a₂*t=2.9*8-1.7*2.7 m/s