Initial momentum must equal final momentum
V = initial velocity of the blocks, v = final velocity of the two
2VM – VM = 3Mv
MV = 3Mv
v = ⅓V
initial KE = ½MV² + ½2MV² = 1.5MV²
final KE = ½3Mv²
Lost KE = 1.5MV² – ½3Mv²
substituting v = ⅓V
Lost KE = 1.5MV² – ½3M(⅓V)²
Lost KE = 1.5MV² – ½3(1/9)MV²
Lost KE = 1.5MV² – (1/6)MV²
Lost KE = 1.333MV²
and that is (d)
(D) 4/3 Mv2
The two blocks of masses M and 2M shown above initially travel at the same speed v but in opposite directions. They collide and stick together. What is the final velocity of the mass M after the collision?
negative one sixth v.
negative one third v.
Zero
one sixth v.
one third v.
1 answer
1 answer