A projectile of mass m moves to the right with a speed v i . The projectile stri
ID: 1391403 • Letter: A
Question
A projectile of mass m moves to the right with a speed vi. The projectile strikes and sticks to the end of a stationary rod of mass M, length d, pivoted about a frictionless axle perpendicular to the page through O. We wish to find the fractional change of kinetic energy in the system due to the collision. (Use any variable or symbol stated above as necessary.)
(b) What is the magnitude of the angular momentum of the system before the collision about an axis through O?
(c) What is the moment of inertia of the system about an axis through O after the projectile sticks to the rod?
RAExplanation / Answer
part b
linear momentum = mass*velocity = m*v
angular momentum = linear momentum* lever arm
angular momentum before collision Li = m*v*d/2
partc)
moment of inertia = I = moment of inertia of rod + moment of inertai of projectile
I = (1/12)*M*d^2 + m*(d/2)^2 = (1/12)*M*d^2 + m*d^2/4