Question

5. A car advertisement states that a certain car can accelerate from rest to 70 m/s in 7

seconds. Find the car's average acceleration.
O-0.10 m/s^2
10 m/s^2
-10 m/s^2
O 0.10 m/s^2

Answer 1

The car's average acceleration is
`10\ m/s^2`.

Step-by-step explanation:

Constant Acceleration Motion

It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.

Being vo the initial speed, a the constant acceleration, vf the final speed, and t the time, the following relation applies:

`v_f=v_o+at`

If we need to find the acceleration, we solve the above equation for a:

`\displaystyle a=(v_f-v_o)/(t)`

The car accelerates from rest (vo=0) to vf=70 m/s in t=7 seconds. Substitute the values into the formula:

`\displaystyle a=(70-0)/(7)=(70)/(7)=10`

`a=10\ m/s^2`

The car's average acceleration is
`10\ m/s^2`.

Note: The choices are not very clear, but the second choice seems to be the correct answer.