Question

The speed of a car is decreased uniformly from 30. meters per second to 10. meters per second in 4.0 seconds. What was the car's acceleration ?

Answer 1

Hello!

The speed of a car is decreased uniformly from 30. meters per second to 10. meters per second in 4.0 seconds. What was the car's acceleration ?

We have the following data:

V (final velocity) = 10 m/s

Vo (initial velocity) = 30 m/s

ΔV (speed interval) = V - Vo → ΔV = 10 - 30 → ΔV = - 20 m/s

ΔT (time interval) = 4.0 seconds

a (average acceleration) = ? (in m/s²)

Formula:

`\boxed{a = \frac{\Delta{V}}{\Delta{T}}}`

Solving:

`a = \frac{\Delta{V}}{\Delta{T}}`

`a = (-20\:(m)/(s))/(4.0\:s)`

`\boxed{\boxed{a = - 5\:(m)/(s^2)}}\:\:\:\:\:\:\bf\green{\checkmark}`

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`\bf\red{I\:Hope\:this\:helps,\:greetings ...\:Dexteright02!}`

Answer 2

Acceleration (magnitude anyway) = (change in speed) / (time for the change) .

Change in speed = (10 - 30) = -20 m/s

Time for the change = 4.0sec

Magnitude of acceleration = -20/4 = -5 m/s²