Question

The speed of the car v (t) after the start of braking is v (t) = 25 -0.12t^2? (where the time t is seconds). = a) How long does braking last? b) how far the car travels during the first 3 and the last 3 seconds from the start of braking? c) how long does the car travel during braking?​

Answer 1

Step-by-step explanation:

Initial speed of the car A u=52 kmh

−1

=52×

18

5

=14.44 ms

−1

The car stops in 5 seconds i.e v=0 at t=5

(A) : Initial speed of the car A u=3 kmh

−1

=3×

18

5

=0.83 ms

−1

The car stops in 10 seconds i.e v=0 at t=10

With the help of these initial and final points for both the cases, we can plot the graph of speed vs time.

Area under the speed-time graph gives the distance covered.

∴ Distance covered by car A x

A

=

2

1

×14.44×5=36.1 m

∴ Distance covered by car A x

B

=

2

1

×0.83×10=4.15 m

Thus car A travels more distance than B.

solution