Need help finding speed and traveling distance for this physics problem?

2015-02-19T15:00:33Z

A 400-kg car is at rest. A forward variable force F = 2000t Newton (t is time in s) are acted on the car. What is the speed and traveling distance after 5.0 s?

oldprof2015-02-19T18:30:11Z

A m = 400-kg car is at rest. A forward variable force F(t) = 2000t Newton (t is time in s) are acted on the car. What is the speed and traveling distance after T = 5.0 s?

We have A(t) = F(t)/m so Aavg = Favg/m = 1/(mT) * INT(2000 t dt)|0 to 5 = (1/5)*1000*25/400 = 12.5 m/s^2.

In which case:

V = Aavg T = 12.5*5 = 62.5 m/s
S = 1/2 Aavg T^2 = (1/2)*12.5*25 = 156 m. ANS.

Alex Gallenberger2015-02-19T15:06:30Z

Looks like an impulse problem. Impulse is force*time.

Force*time = mass*(change in velocity)

Using this equation,

2000(5) = 400(change in velocity)

25m/s = change in velocity

Since it started at rest, your speed after 5s is 25m/s