Question

a car enters freeway with speed of 6.4m/s and accelerates uniformly for 3.2 Km in 3.5 min.how fast in m/s is the car moving after. this time

Answer 1

equation could be

v^2=u^2+2as

u=6.4, s=3.2, a= ???

Answer 2

Answer:

The car is moving at 24.04 m/s after 210 seconds

Explanation:

We have equation of motion s = ut+0.5at², t is time, u is initial velocity, a is acceleration and s is displacement.

Acceleration, a = ?

Initial velocity, u = 6.4 m/s

displacement, s = 3.2 km = 3200 m

Time, t = 3.5 min = 210 s

Substituting

          s = ut+0.5at²

          3200 = 6.4 x 210 + 0.5 x a x 210²

                a = 0.084 m/s²

We have equation of motion v = u + at, v is the final velocity

             v = 6.4 + 0.084 x 210

             v = 24.04 m/s

The car is moving at 24.04 m/s after 210 seconds