Block A has mass 1.00 kg , and block B has mass 3.00 kg . The blocks are forced together, compressing a spring S between them; then the system is released from rest on a level, frictionless surface. The spring, which has negligible mass, is not fastened to either block and drops to the surface after it has expanded. Block B acquires a speed of 1.20 m/s.
2 Answers
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1)
pA=pB
p=m*v
mA*vA=mB*vB
vA=(mB*vB)/mA
vA=(3kg*1.2m/s)/1kg
vA=3.6m/s
2)
UA= -KA = -(mA*vA^2)/2 = -(1kg*3.6m/s^2)/2 = -6.48J
UB = same process as before = -2.16J
U= UA+UB = -8.64J
Source(s): My last physics course (not a good teacher so sorry if there is any mistake) -
The answer is not negative. It is 8.64J
