Question

A car travelling at a speed of 40 m/s slows to 10 m/s in 5 seconds. The acceleration of the car is

Answer 1

`\boxed {\boxed {\sf -6 \ m/s^2}}`

Step-by-step explanation:

Acceleration is the change in velocity with respect to time. We are given the velocity and time, so we will use the following formula to find acceleration.

`a= \frac {v_f-v_i}{t}`

The car slowed down, so the final velocity was 10 meters per second and the initial velocity was 40 meters per second. It slowed down in 5 seconds.

• 
  `v_f`= 10 m/s
• 
  `v_i`= 40 m/s
• t=5 s

Substitute these values into the formula.

`a= ( 10 \ m/s - 40 \ m/s)/(5 \ s)`

Solve the numerator and subtract.

`a= ( -30 \ m/s)/(5 \ s)`

Divide.

`a= -6 \ m/s/s`

`a= -6 m/s^2`

The acceleration of the car is -6 m/s² or -6 meters per second squared. The acceleration is negative because the car slowed down.