PHYS-114 Test #3 Chapters 9,10,11 Winter 2008
(Conservation of Momentum and Energy)
Name (please print): _____________________________________
Raw Score: _________ Test Grade: ___________
[1] (8 pts) In an episode of Futurama Professor Farnsworth uses his Smell-O-Scope to detect a gigantic
ball of garbage, with a mass of 7.4×105 kg, that is hurtling towards the earth at a speed of 2400 m/s. Fry
saves the day by suggesting that the New New Yorkers create a second huge ball of garbage and launch it
towards the first one. If the second garbage ball has a mass of 5.3×105 what would its velocity have to be
in order for it to stick to the first ball and stop, making it come to rest? (Draw before and after pictures)
[3] (10 pts) Two blocks (mA = 0.6 kg and mB = 0.25 kg) are connected by a string passing over a
massless, frictionless pulley. Both blocks are attached to springs, with
kA = 44 N/m and kB = 18 N/m. Spring A is initially stretched to the left a
distance of 0.87 m from its equilibrium point, while spring B is at its
equilibrium point. The system is released from rest, and block B begins
to move upwards. Find the speed of block B when block A is passing
through its equilibrium point. (include an end picture)
