Word ProNems:

1. A car goes from 4.47 m/s to 17.9 m/s in 3 seconds.

a. Did this car speed up or slow down?

b. Should your answer be positive or negative? Explain your reasoning.

c. Calculate the acceleration of the car.

a:it speed up

b:it should be positive since final

velocity is larger than initial velocity

c:acceleration is approximately 4.5

m/s^2

Explanation:

initial velocity=u=4.47m/s

Final velocity=v=17.9m/s

Time=t=3 seconds

a:the car speed up since the velocity

increased

b:change in velocity is positive

because final velocity is larger than

initial velocity

17.9-4.47=13.43 m/s

c: acceleration = (v-u) / t

acceleration = (17.9-4.47) / 3

acceleration=13.43/3

acceleration=4.5 m/s^2