The velocity of an object with a mass of 2 kg2kg is given by v(t)= t^3 + 3 t^2 v(t)=t3+3t2. What is the impulse applied to the object at t= 4 t=4?

1 Answer
Feb 26, 2016

I (4) =2 (4*4^2 +3*4^2) = 7*4^2 = 112 N sI(4)=2(442+342)=742=112Ns
Careful however Impulse is not mv(t)mv(t) evaluate at t = 4 st=4s
it is Force applied for a finite amount of time F*Deltat
in the limit I = int_(t_1)^(t_(2))Fdt

Explanation:

This is a straight implementation of the impulse equation i.e.
F = m(dv)/dt Newton law ==> (1)
I = F dt = m(dv) Impulse equation ==> (2)
While the question is not clear I will make the assumption the Force was applied for 4 seconds causing the change in speed from
v(0) = 0 -> v(4) and I (4) =2 (4*4^2 +3*4^2) = 7*4^2 = 112 N s