Question

A car slows down from 27.7 m/s
to 10.9 m/s in 2.37 s.
What is its acceleration?

Answer 1

- 7.088 m/s²

Step-by-step explanation:

As we know that,

★ Acceleration = Change in velocity/Time

→ a = (v - u)/t

Here,

• Initial velocity (u) = 27.7 m/s
• Final velocity (v) = 10.9 m/s

→ a = (10.9 m/s - 27.7 m/s)/2.37 s

→ a = -16.8/2.37 m/s²

→ a = -7.088 m/s² [Answer]

Negative sign denotes that the velocity is decreasing.

Answer 2

`\boxed {\boxed {\sf -7.09 \ m/s^2}}`

Step-by-step explanation:

We are asked to find the acceleration of a car. Acceleration is the change in velocity with respect to time. We will use the following formula:

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

In this formula,
`v_f` is the final velocity,
`v_i` is the initial velocity, and
`t` is the time. The car slows down from 27.7 meters per second to 10.9 meters per second in 2.37 seconds. Therefore:

• 
  `v_f`= 10.9 m/s
• 
  `v_i`= 27.7 m/s
• 
  `t`= 2.37 s

Substitute the values into the formula.

`a= ( 10.9 m/s-27.7 m/s)/(2.37 \ s)`

Solve the numerator.

• 10.9 m/s - 27.7 m/s= -16.8 m/s

`a= (-16.8 \ m/s)/(2.37 \ s)`

Divide.

`a= -7.088607595 \ m/s/s`

`a= -7.088607595 \ m/s^2`

The original measurements of velocity and time have 3 significant figures, so our answer must have the same. For the number we found, that is the hundredth place. The 8 in the thousandth place tells us to round the 8 in the hundredth place up to a 9.

`a \approx - 7.09 \ m/s^2`

The acceleration of the car is approximately -7.09 meters per second squared. The acceleration is negative because the car is slowing down.