Question

What is the acceleration if a car slows down from 30 m/s to 15 m/s in 4 seconds?

Answer 1

`\boxed{\sf Acceleration \ (a) = -3.75 \ m/s^2}`

Given:

Initial velocity (u) = 30 m/s

Final velocity (v) = 15 m/s

Time taken (t) = 4 seconds

To Find:

Acceleration (a) of the car

Step-by-step explanation:

From equation of motion we have:

`\boxed{ \bold{v = u + at}}`

By substituting value of v, u & t in the equation we get:

`\sf \implies 15 = 30 + 4a \\ \\ \sf \implies 4a + 30 = 15 \\ \\ \sf \implies 4a = 15 - 30 \\ \\ \sf \implies 4a = - 15 \\ \\ \sf \implies a = - (15)/(4) \\ \\ \sf \implies a = - 3.75 \: m {s}^( - 2)`

`\therefore`

Acceleration (a) of the car = -3.75 m/s²

Answer 2

11.25

Step-by-step explanation:

acceleration =v-u/t

=-30-15/4

=-45/4

=11.25

hope it helps