Question

A car, initially traveling at 15 meters per second

Answer 1

The magnitude of the acceleration of the car is given by:
$a= \frac{v_f-v_i}{t}$
where
$v_i=15 m/s$ is the initial speed of the car
$v_f=25 m/s$ is the final speed of the car
$t=4.0 s$ is the time it takes for the car to change its speed

Substituting these data into the formula, we find the magnitude of the average acceleration of the car:
$a= \frac{25 m/s-15 m/s}{4.0 s}=2.5 m/s^2$

therefore, the correct answer is (1) 2.5 m/s^2.