MODULE 4
A. Introduction / Terms & Objectives
Momentum, p = mv: is the product of the mass and velocity of an object.
Impulse-Motion, mv1 + F(Δt) = mv2: is the first particles momentum plus the product of the
force exerted and the change in time, all equal to the second particles momentum.
Law of Conservation of Momentum (Impact), p1i + p2i = p1f + p2f: the sum of the initial
momentums of two particles equals the sum of the final momentums of the two particles.
Common Definitions and Background Knowledge Needed:
Weight = (Mass)*(Gravity): W = mg
Gravity, g = 9.81 m/s2 or 32.2 ft/s2
1 Meter = 3.281 Feet
1 Meter = 100 Centimeters = 1000 Millimeters
Convert m/s into mph – 1 m/s = 2.24 mph
Algebra Skills
Word Problems Solving Skills
B. Methodology
Steps to solving the problem:
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6.
Draw a Free Body Diagram, FBD, of the given problem statement.
Label all forces acting on the FBD.
Write Given information and what you need to Find.
Write equations relevant to problem needed to solve.
Solve the problem.
Box in answer and use appropriate units and significant figures.
C. Problem Statement
Momentum
Problem 1: A train is rolling down the track at a velocity of 50 m/s. The train has a mass of
1,000,000 kg. What is the momentum of the train?
Train Animation
Problem 2: If the same train from the problem 1 has just lost its brakes while going down a hill
but is now at the bottom leveled out on flat ground and the momentum was increased by 50%,
what is the trains new velocity, (a) m/s and (b) mph?
Impulse-Motion
Problem 1: A 440 kg sailboat with its occupants is sailing downwind at 12 km/h when its sail is
raised to increase its speed. Determine the force needed by the sail over the 10 second interval
that it takes for the boat to reach a final speed of 18 km/h.
Law of Conservation of Momentum (Impact)
Problem 1: A pool player uses the queue ball to hit the 8-ball into the pocket of the pool table
to win the Pool Hall Championship. The queue ball has a mass of 0.12 kg and the 8 ball has a
mass of 0.1 kg If the 8 ball is initially sitting at rest, V2i = 0, and the queue balls final velocity
after impact is also at rest, V1f = 0, what is the final velocity of the 8 ball, V2f, after impact if the
queue balls initial velocity, V1i, is 10 m/s?
Pool Table Animation
Problem 2: Two bowling balls are on the same track heading towards each other. Ball 1 has a
mass of 300 kg and Ball 2 has a mass of 500 kg. If Ball 1 and Ball 2 have the same initial
velocities of 15 m/s and Ball 2 has a finial velocity of 10 m/s, what is the final velocity of Ball 1?
Bowling Ball Animation
D. Application
Students must work their own problem after learning the methodology. The problems assigned
will allow the students to comprehend the principles needed to better apply the knowledge to
realistic applications.
E. Assessment
Quiz questions hitting the high points of the module