The coins collide elastic ally; calculate both their final speeds. What are the
ID: 1446072 • Letter: T
Question
The coins collide elastic ally; calculate both their final speeds.
What are the directions of their final velocities? Problem 8.30 Part A On a cold winter day, a penny (mass 2.50 g) and a nickel (mass 5.00 g) are lying on the smooth frictionless) surface of a frozen lake With your finger, you fick the penny toward the nickel wth a speed of 2.45 m/s The coins collide edastically, calculate both their final speeds m/s Upenny Vuickel Submit My Answers Give Up Part B What are the directions of their final velocities? The drections of velocities are the opposite O The directions of velocities are the same. Submit My Ariswers Gree Up Continue
Explanation / Answer
m1 = 2.5 g
m2 = 5 g
u1 = 2.45 m/s
Elastic collision
Conservation of momentum and energy
m1 u1 + m2 u2 = m1 v1 + m2 v2
0.5 m1 u1^2 + 0.5 m2 u2^2 = 0.5 m1 v1^2 + 0.5 m2 v2^2
2.5 * 2.45 + 5 * u2 = 2.5 * v1 + 5 * v2
2.5 * 2.45^2 + 5 * u2^2 = 2.5 * v1^2 + 5 * v2^2
u2 = 0
Solving above 2 eqns, we get
v1 = - 0.816 m/s
v2 = 1.633 m/s
Direction of their final velocities are opposite