Answer:
A. - 12.01 m/s
B. Kinetic energy before collision = 52.488 J
Kinetic energy after collision = 13.40 J
Explanation:
Parameters given:
Mass of ball = 144g = 0.144kg
Initial velocity of ball = 27 m/s
Mass of brick = 5.25kg
Initial velocity of brick = 0 m/s
Final velocity of brick = 1.07m/s
A. To find the Final velocity of the ball, we use the law of conservation of momentum i.e.
Total initial momentum = Total final momentum
Initial momentum of ball = m*u
= 0.144 * 27
= 3.888 kgm/s
Initial momentum of brick = m*u
= 5.25 * 0
= 0 kgm/s
Total initial momentum = 3.888 + 0
= 3.888 kgm/s
Final momentum of ball = 0.144 * v
= 0.144v
Final momentum of brick = 5.25 * 1.07
= 5.6175 kgm/s
Total final momentum = 0.144v + 5.6175
Hence,
3.888 = 0.144v + 5.6175
=> 0.144v = 3.888 - 5 6175
0.144v = -1.7295
v = - 1.7295/0.144
v = - 12.01m/s
Therefore, the final velocity of the ball is - 12.01m/s. The negative sign indicates that it's moving opposite to the initial velocity.
B. Kinetic energy of ball before collision =
0.5 * m * u^2
= 0.5 * 0.144 * 27^2
= 52.488 J
Kinetic energy of the brick before collision =
0.5 * 5.25 * 0
= 0 J
Total kinetic energy before collision is:
52.488 + 0 = 52.488 J
Kinetic energy of ball after collision
= 0.5 * 0.144 * (12.01)^2
= 10.39J
Kinetic energy of brick after collision
= 0.5 * 5.25 * 1.07^2
= 3.01 J
Total kinetic energy after collision
= 10.39 + 3.01
= 13.40 J
