Posted by Heart on .
A race car has a mass of 710 kg. It starts from rest and travels 40.0 m in 3.0 s. The car is uniformly accelerated during the entire time. What net force is exerted on it?

physics =) 
MathMate,
First calculate the acceleration from the distance and time using the formula:
S=v0t+(1/2)at²
where
a=acceleration
S=distance
v0=initial velocity
t=time
a=2(Sv0t)/t² (assumed uniform)
Find force F from
F=ma 
physics =) 
Heart,
Thanks a lot! I got F = 6311.11 N.

physics :) 
MathMate,
The answer is correct!
Have a merry Christmas, and enjoy your holidays! 
physics =) 
drwls,
F*X = KE increase = (1/2) M Vfinal^2
Vfinal = 2*Vaverage = 2*X/T =2*(40/3) = 26.67 m/s
F = (1/2)*(710)*(26.67)^2/40 = 6313 N
We agree