If a car starts at rest and increase to a final velocity of 50 mi/hr north over a time of 5 hours, what is its average acceleration?

a. 10 mi/hr
b. 250 mi/hr
c. 10 mi/hr^2
d. 250 mi/hr^2

2 Answers
Feb 13, 2018

Average acceleration is the change in velocity divided by the change in time

Explanation:

So, if the car starts at rest, the initial velocity is zero. The initial time is also zero.

Then #frac{\Deltav}{\Deltat}=\frac{v_f-v_0}{Deltat}=\frac{50mph-0}{5hrs}=10mph^2#

Feb 14, 2018

#c.#

Explanation:

Well, acceleration is defined as,

#a=(dv)/dt#

where

#dv# is the change in velocity

#dt# is the change in time

Since the car starts at rest, it has a velocity of #0mi"/"hr#.

#:.a=(50mi"/"hr-0mi"/"hr)/(5hr)#

#a=(50mi"/"hr)/(5hr)=10mi"/"hr^2#

So, option #c.# is correct.