A 2.0 kg block of iron slides along a floor, decreasing its speed from 4.0 m/s to 1.0 m/s.

Question

a) How much work does the frictional resistance of the floor do on the block?
b) If the reduction in velocity occurred over a distance of 10 m, what was the force of
friction acting on the block?
c) What impulse was delivered to the block?

Answer 1

work = change in Ke
= (1/2)(2)(1^2-4^2) = -15 J
negative because energy taken out not put in

work = force * distance in direction of force
-15 = F (10)
F = -1.5 N

impulse = change in momentum
I = 2 ( 1 - 4) = -6 kg m/s

Answer 2

THANKS