Question

A car traveling 34 mi/h accelerates uniformly for 4 s, covering 615 ft in this time. What was its acceleration? Round your answer to the nearest 100th place. Answer in units of ft/s^2. What is the final velocity at this time? Answer in units of ft/s.

Answer 1

51.94 ft/s²

257.63 ft/s

Step-by-step explanation:

t = Time taken = 4 s

u = Initial velocity = 34 mi/h

v = Final velocity

s = Displacement = 615 ft

a = Acceleration

Converting velocity to ft/s

`34\ mi/h=(34* 5280)/(3600)=49.87\ ft/s`

Equation of motion

`s=ut+(1)/(2)at^2\\\Rightarrow a=2(s-ut)/(t^2)\\\Rightarrow a=2\left((615-49.87* 4)/(4^2)\right)\\\Rightarrow a=51.94\ ft/s^2`

Acceleration is 51.94 ft/s²

`v=u+at\\\Rightarrow v=49.87+51.94* 4\\\Rightarrow v=257.63\ ft/s`

Final velocity at this time is 257.63 ft/s