Question

With good tires and breaks, a car traveling 50 mi/hr on dry pavement can travel 400 ft when the driver reacts to something he sees and brings the vehicle to a stop. If this is done uniformly, what is the car's acceleration?

Answer 1

Answer:
`6.72 m/s^2`

Step-by-step explanation:

Given

initial velocity
`u=50 mi/hr\approx 73.33 ft/s`

Distance traveled before stopping
`s=400 ft`

using equation of

`v^2-u^2=2as`

where v=final velocity

u=initial Velocity

a=acceleration

s=displacement

v=0 as car stops after travelling
`400 ft`

`0-73.33^2=2* a* 400`

`a=-6.72 m/s^2`

negative sign indicates it is deceleration