Question

A car is initially traveling south at a speed of 10.9m/s. The brakes are applied and the car comes to a stop over a distance of 39.2 meters. Find the car's acceleration.

Answer 1

Answer:
`-1.51 m/s^(2)`

Step-by-step explanation:

Since the car is moving in a single direction, we can use the following kinematic equation to find its acceleration
`a`:

`V^(2)=V_(o)^(2)+2ad`

Where:

`V=0 m/s` is the car's final velocity (we are told it comes to a stop)

`V_(o)=10.9 m/s` is the car's initial velocity

`a` is the car's acceleration

`d=39.2 m` is the distance travelled by the car

Isolating
`a`:

`a=(V^(2)-V_(o)^(2))/(2d)`

Solving the equation with the given data:

`a=((0 m/s)^(2)-(10.9 m/s)^(2))/(2(39.2 m))`

Finally, the acceleration is:

`a=-1.51 m/s^(2)` Note the negative sign indicates the car was decreasing its velocity before coming to a stop.