Question

A car accelerating from rest for 20s to reach velocity of 15 m/s and it keeps on. moving with this velocity for 50s an then it applied the break
Stop in 30s what is the displacement?

WILL GIVE BRAINLY best answer with steps

Answer 1

Answer:

1125m

Explanation:

The car moves with a uniformly accelerated motion for 20s:

s = 1/2·a·t² + v0·t + s0 (note that vo = 0 and s0 = 0, with v0 being the initial velocity and s0 the initial displacement).

So: s = 1/2·a·t²

The acceleration will be: Δv/Δt = 15m/s / 20s = 0.75 m/s²

s1 = 1/2·0.75 m/s² · (20 s)^2 = 150m

Then it continues with the velocity he acquired (v = a·t = 0.75 m/s²·20s = 15 m/s):

s2 = vt = 15m/s·50s = 750m

The final acceleration, when stopping, will be:

a = Δv/Δt = -15m/s / 30s = -1/2 m/s²

s3 = 1/2·(1/2m/s²)·(30s)² = 225m.

Now we sum s1 with s2 and s3:

s1 + s2 + s3 = 150m + 225m + 750m = 1125m