Bullet Problem 5 block mi 10 kg and m225 kg collides head on

Bullet Problem 5 block mi 1.0 kg and m2-2.5 kg collides head on as shown in the following figure. The is frictionless. The velocities of the two masses after collision are shown i (a) What was the velocity v of mass m2 before collision? (b) Is the collision elastic? [Show your work in support of your answer. A simple \'yes \" or \"No answer without any work is worth nothing 5.0 m/s 1.0 kg 2.5 kg Before collision 2.0 m/s 4.0 m/s 1.0 kg 2.5 kg After collision nqual narts at some h Problem 6

Solution

here,

m1 = 1 kg

m2= 2.5 kg

a)

let the initial velocity of seccond ball be v

using conservation of momentum

m1 * 5 + m2 * 2.5 = m1 * 2 + m2 * 4

1 * 5 + 2.5 * v = 2 * 1 + 4 * 2.5

solving for v

v = 2.8 m/s

b)

initial kinetic energy , KEi = 0.5 * m1 * 5^2 + 0.5 * m2 * v^2

KEi = 0.5 * 1 * 5^2 + 0.5 * 2.5 * 2.8^2 J

KEi = 22 J

final kinetic energy ,KEf= 0.5 * m1 * 2^2 + 0.5 * m2 * 4^2 J

KEf = 0.5 * 1 * 4 + 0.5 * 2.5 * 16 J

KEf = 22 J

as KEi = KEf

the collison is elastic