A 4N Force acts on a 3 kg object moving at 8 m/s fir 10 sec. Can some one help me answer this problem? showwrk

Question

questions:
What is the object's change in momentum?
what impulse acts on the object?
What is the objects final speed?

my teacher trys to teach us but goes on even if the whole class doesnt understand...Plz Help me!

Answer 1

The formula for impulse I is I = FΔt = mΔv.

a and b are the same, because the impulse is the change in linear momentum.
I = FΔt = 4N * 10 sec = 40 N*s.

c is a problem, because Force and Velocity are vectors - they are directional. To answer the problem, you need to know (since it's assumed in 2 diminsions) whether the Force and the initial Velocity are in the same direction or opposite directions. The change in velocity can be determined by:
I = mΔv
40 = 3 kg * Δv
40/3 = Δv = 13.3333

The final velocity is either 8 + 13.3333 = 21.3333 m/s if you push in the same direction it was already travelling, or 8 - 13.3333 = -5.3333 m/s if you push in the opposite direction.