For a closed system, the momentum is always conserved. Momentum of an object is given by mv where m is the mass and v is the velocity.
Momentum of the system before the collision is given by:p1 + p2 = 1.2*1.2 + x*4.4 (where x is the mass of the 2nd block);
Momentum of the system after the collision is given by:
Mv where M is the combined mass of the 2 blocks as they stick together and v is the velocity.Momentum = (1.2+x)*3.2
As the momentum is conserved i.e momentum before collision and after collision is the same:(1.2+x)*3.2 = 1.2*1.2 + 4.4*xEvaluate x to get the mass of the 2nd block.
b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle