A car has a mass of 710 kg. It starts from rest and travels 40.0 m in 3.0s. The car is uniformly accelerated during the entire time. How big is the net force acting on the car?

1 Answer
Dec 4, 2015

6300 "N"6300N

Explanation:

We will employ the following equation of kinematics

x = 1/2at^2x=12at2

which describes an object traveling in one dimension with a constant acceleration and an initial velocity of zero.

We know the displacement and the time elapsed so we may solve for the acceleration:

40.0 "m" = 1/2a(3.0"s")^240.0m=12a(3.0s)2

Solving for aa yields:

a = 8.89 "m"/"s"^2a=8.89ms2

Now, knowing the acceleration of the car as well as the mass of the car we can apply Newton's second law, which states

F_("net") = maFnet=ma

All we need to do is plug in our values for mm and aa:

F_("net") = 710"kg"*8.89 "m"/"s"^2 = 6311.9 "N"Fnet=710kg8.89ms2=6311.9N

Considering the fact that our final answer should have only two significant digits, we will round to the nearest hundred:

F_("net") = 6300 "N"Fnet=6300N