Impulse Momentum Exam 1 and Problem Solutions

1. An object travels with a velocity 4m/s to the east. Then, its direction of motion and magnitude of velocity are changed. Picture given below shows the directions and magnitudes of velocities. Find the impulse given to this object. Impulse Momentum I=F.Δt=Δp=m.ΔV

where ΔV=V₂-V₁=-3-4=-7m/s

I=m.ΔV=3.(-7)=-21kg.m/s

2. Ball having mass 4kg and velocity 8m/s travels to the east. Impulse given at point O, makes it change direction to north with velocity 6m/s. Find the given impulse and change in the momentum. Impulse Momentum Initial and final momentum vectors of ball are shown in the figure below. Impulse Momentum P₁=m.V₁=4kg.8m/s=32kg.m/s

P₂=m.V₂=4kg.6m/s=24kg.m/s

ΔP=P₂+P₁ (vector addition)

ΔP²=P₂²+P₁²=m²(v₂²+v₁²)

ΔP₂=16.100

ΔP=40kg.m/s

Impulse=change in momentum

I=ΔP=40kg.m/s

3. Find the impulse and force which make 12m/s change in the velocity of object having 16kg mass in 4 s.

F.Δt=ΔP=m.ΔV

F.4s=16kg.12m/s

F=48N

F.Δt=Impulse=192kg.m/s

4. Applied force vs. time graph of object is given below. Find the impulse of the object between 0-10s. Impulse Momentum Area under the force vs. time graph gives us impulse.

F.Δt=20.2/2+20.(6-2)+20.(10-6)/2

F.Δt=140kg.m/s

5. A ball having mass 500g hits wall with a10m/s velocity. Wall applies 4000 N force to the ball and it turns back with 8m/s velocity. Find the time of ball-wall contact.

F.Δt=ΔP=m.ΔV=m.(V₂-V₁)

-4000.Δt=0,5kg.(8-10)

Δt=0,00025s