Two blocks have a mass M and 3M are placed on a horizontal frictionless surface
Answers
Question:-
Two blocks of M and 3M are placed on a horizontal, frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord initially holding the blocks together is burned; after this, the block of mass 3M moves to the right with a speed of 2.00 m/s
(a) What is the speed of the block of mass M?
(b) Find the original elastic energy in the spring if M = 0.30 kg
Given,
Answer:-
The initial velocity of both the bodies V initial =0
Initial momentum is zero.
Final Velocity of 3M block V B =2m/s
Mass of block A=M
Mass of block B=3M
Apply conservation of momentum
Final momentum = initial momentum
3MV B + MV A = 0
V A = -3V B =-−3×2=−6m/s
Given,
Mass M=0.30kg
Energy in spring = final kinetic Energy of both Masses
K.E= 1÷2 MV A 2 + 1÷2 (3M)V B 2
K.E= 1 ÷2 0.3×(−6) ²+ 1 ÷2 (3×0.3)2 ²=7.2 J
(a) Speed of block mass M is 6m/s
(b) Total Kinetic Energy is 7.2J