a = change in v / change in time
= (12-2)/2 = 5 m/s^2
m Vi = 1500 * 2 = 3000 kg m/s
m Vf = 1500 * 12 = 18,000 kg m/s
18,000 - 3000 = 15,000 kg m/s
F = rate of change of momentum
= m a
do both ways
F = 15,000/2 = 7,500 N
or
F = 1500 * 5 = 7,500 N
remarkable LOL
Now
What Newton actually said was
F = rate of change of momentum
but
that is d/dt ( m v)
BUT
usually m is constant
so
we say F = m dv/dt but dv/dt is a
so F = m a
If you are doing a problem like a rocket expelling fuel where the mass is not constant, it helps to remember that F = d/dt (m v)
:)
You accelerate your 1500 Kg car from 2 m/s to 12 m/s in 2 seconds. How do you determine
the cars acceleration
initial momentum
final momentum
change in momentum
the force required to do this?
1 answer