A) The change in momentum of an object is given by:
Δp = m×(Vf-Vi)
m is the mass, Vi is the initial velocity, and Vf is the final velocity.
Given values:
m = 500kg
Vi = 15m/s
Vf = 30m/s
Plug in the values and solve for Δp:
Δp = 500×(30-15)
Δp = 7500kg×m/s
B) One equation for the average force exerted on an object is given by:
F = Δp/Δt
F is the average force, Δp is the change in momentum, and Δt is the amount of elapsed time.
Given values:
Δp = 7500kg×m/s (from part A)
Δt = 5s
Plug in the values and solve for F:
F = 7500/5
F = 1500N
C) The wording in this question is a little strange. To clarify, we calculated the average force, which required the assumption that the car's velocity was changing at a constant rate. This very well may not be the case. Under non-uniform acceleration, the car's engine would at certain times provide a force less than the average force, and at other times the car's engine would provide a force greater than the average.
