A driver brings a car to a full stop in 2.0 s. If the car was initially
traveling at 22 m/s, what is the acceleration?
a -17 m/s2
b 27 m/s2
c 7 m/s2
d –11 m/s2

Respuesta :

Answer:

[tex]\boxed {\boxed {\sf D. \ -11 \ m/s^2}}[/tex]

Explanation:

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

[tex]a=\frac{v_f-v_i}{t}[/tex]

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.

[tex]v_f=0 \ m/s\\v_i=22 \ m/s\\t= 2.0 \ s[/tex]

Substitute the values into the formula.

[tex]a=\frac{0 \ m/s-22 \ m/s}{ 2.0 \s }[/tex]

Subtract in the numerator first.

  • 0 m/s- 22 m/s = -22 m/s

[tex]a=\frac{-22 \ m/s}{2.0 \ s}[/tex]

Divide.

[tex]a= -11 \ m/s^2[/tex]

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