Question

A driver brings a car to a full stop in 2.0 s. If the car was initially

Answer 1

Answer:

$\boxed {\boxed {\sf D. \ -11 \ m/s^2}}$

Explanation:

Acceleration can be found by dividing the change in velocity by the time.

$a=\frac{v_f-v_i}{t}$

where Vf is the final velocity, Vi is the initial velocity, and t is the time.

Since the car came to a complete stop, it's final velocity was 0 meters per second.

The initial velocity was 22 meters per second.

The time was 2.0 seconds.

$v_f=0 \ m/s\\v_i=22 \ m/s\\t= 2.0 \ s$

Substitute the values into the formula.

$a=\frac{0 \ m/s-22 \ m/s}{ 2.0 \s }$

Subtract in the numerator first.

• 0 m/s- 22 m/s = -22 m/s

$a=\frac{-22 \ m/s}{2.0 \ s}$

Divide.

$a= -11 \ m/s^2$

The acceleration of the car was -11 meters per square second. The negative acceleration indicates slowing down/stopping.