Question

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

Answer 1

Answer:

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

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:

$\displaystyle a=\frac{v_f-v_o}{t}$

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

$\displaystyle a=\frac{70-0}{7}=\frac{70}{7}=10$

$a=10\ m/s^2$

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.