Ok, so I'm preparing for a physics exam which is tomorrow, and I'm currently studying Newton's law, etc, and the equation and whatnot. So, I come across this question:
A car is moving at a constant velocity of 20 km/h (5.56 m/s). How much net force is required to raise its velocity to 50 km/h (13.89 m/s) in 30 seconds? Suppose the car has a mass of 150 kg.
And this one:
If the net force of 7 N was continuously applied on 400 g object at rest, how long will it take to raise its velocity to 80 m/s?
It's asking that I find seconds and whatnot, but the equations that I have to work with don't have a time unit in them. *eye twitch*
Can someone help me? Quickly? Perferably by the end of the night.
The equations are here:
F = ma
W = mg
FN = - mg
F
f = uF
n
The u thing isn't actually a u, but something weird looking. Anyways. Please help? ^__^