Answer:
The car's average acceleration is [tex]10\ m/s^2[/tex].
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:
[tex]v_f=v_o+at[/tex]
If we need to find the acceleration, we solve the above equation for a:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
The car accelerates from rest (vo=0) to vf=70 m/s in t=7 seconds. Substitute the values into the formula:
[tex]\displaystyle a=\frac{70-0}{7}=\frac{70}{7}=10[/tex]
[tex]a=10\ m/s^2[/tex]
The car's average acceleration is [tex]10\ m/s^2[/tex].
Note: The choices are not very clear, but the second choice seems to be the correct answer.
