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A 1.3 kg mass (initially at rest) compresses a spring (spring constant 2600 N/m)

ID: 2194562 • Letter: A

Question

A 1.3 kg mass (initially at rest) compresses a spring (spring constant 2600 N/m) by 0.15 m, and is released. The mass slides along a horizontal, frictionless table until it collides totally (perfectly) inelastically with an identical mass at rest. 1. What is the velocity of the 1.3 kg mass before hitting the second 1.3 kg mass? 2. What is the velocity of the two masses after they collide and stick together? 3. After colliding and sticking together, the two masses move up a frictionless inclined plane. What is the maximum height achieved by the two masses?

Explanation / Answer

energy conservation 0.5*1.3*v^2=0.5*2600*(0.15)^2 v=6.7 m/s the velocity of the 1.3 kg mass before hitting the second 1.3 kg mass=6.7 m/s conservation of momentum 1.3*6.7=(1.3+1.3)*v v=3.35 m/s the velocity of the two masses after they collide and stick together=3.35 m/s conservation of energy 0.5*2.6*3.35^2=2.6*9.81*h h=0.571 m the maximum height achieved by the two masses=0.571 m