Conservation of Momentum Sample Problems

Conservation of Momentum Problem 1 Glider A of mass 0.355 kg moves along a frictionless air track with a velocity of 0.095 m/s. It collides with glider B of mass 0.710 kg moving in the same direction at a speed of 0.045 m/s. After the collision, glider A continues in the same direction with a velocity of 0.035 m/s. What is the velocity of glider B after the collision? REMEMBER: mAvA + mBvB = mAvA‘ + mBvB' KNOWN: mA = 0.355 kg vA = 0.095 m/s mB = 0.710 kg vB = 0.045 m/s vA ‘ = 0.035 m/s UNKNOWN: vB ‘ = ? vB‘ = 0.075 m/s

Conservation of Momentum Problem 2 A 20 g bullet strikes an 8 kg stationary wooden block and embeds itself in the block. The block and the bullet fly off together at 10 m/s. What was the original velocity of the bullet? REMEMBER: mBvB + mWvW = (mB + mW)v' KNOWN: mB = 0.020 kg Since vW = 0, we can eliminate this quantity. mw = 8 kg vW = 0 m/s v' = 10 m/s UNKNOWN: vB = ? vB = 4 x 103 m/s