# Impulse Momentum Exam2 and Problem Solutions

**Impulse Momentum Exam2 and Problem Solutions**

**1.**Objects shown in the figure collide and stick and move together. Find final velocity objects.

Using conservation of momentum law;

m

_{1}.V_{1}+m_{2}.V_{2}=(m_{1}+m_{2}).V_{final}3.8+4.10=7.V

_{final}64=7.V

_{final}V

_{final}=9,14m/s**2.**2kg and 3kg objects slide together, and then they break apart. If the final velocity of m

_{2}is 10 m/s,

a) Find the velocity of object m

_{1}.

b) Find the total change in the kinetic energies of the objects.

a) Using conservation of momentum law;

(m

(m

_{1}+m_{2}).V=m_{1}.V_{1}+m_{2}.V_{2}5.4=30+2.V

_{1}V

_{1}=-5m/sb) E

_{Kinitial}=1/2/m_{1}+m_{2}).V^{2}E

_{Kinitial}=1/2.5.16=40jouleE

_{Kfinal}=1/2.2.5^{2}+1/2.3.10^{2}E

_{Kfinal}=175 jouleChange in the kinetic energy is =175-40=135 joule

**3.**As shown in the figure below, object m

_{1}collides stationary object m

_{2}.

**Find the magnitudes of velocities of the objects after collision. (elastic collision)**

In elastic collisions we find velocities of objects after collision with following formulas;

V

_{1}'=(m_{1}-m_{2})/(m_{1}+m_{2}).V_{1}V

_{2}'=(2m_{1}/m_{1}+m_{2}).V_{1}m

_{1}=6kg, m_{2}=4kg, V_{1}=10m/sV

_{1}'=(6-4/6+4).10=2m/sV

_{2}'=(2.6/6+4).10=12m/s**4.**Momentum vs. time graph of object is given below. Find forces applied on object for each interval.

F.Δt=ΔP

F=ΔP/Δt

Slope of the graph gives us applied force.

I. Interval:

F

_{1}=P_{2}-P_{1}/10-0=-50/10=-5NII. Interval:

F

_{2}=50-50/10=0III. Interval:

F

_{3}=100-50/10=5N

**5.**A box having mass 0,5kg is placed in front of a 20 cm compressed spring. When the spring released, box having mass m

_{1}, collide box having mass m

_{2}and they move together. Find the velocity of boxes.

Energy stored in the spring is transferred to the object m

_{1}.1/2.k.X

^{2}=1/2.mV^{2}50N/m.(0,2)

^{2}=0,5.V^{2}V=2m/s

Two object do inelastic collision.

m

_{1}.V_{1}=(m_{1}+m_{2}).V_{final}0,5.2=2.V

_{final}V

_{final}=0,5m/sImpulse Momentum Exam1 and Problem Solutions< Prev |
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