What is the mass of m1 in a double mass block problem?

[ddawg923]

A mass m1 on a horizontal shelf is attached by a thin string that passes over a frictionless peg to a 2.4 kg mass m2 that hangs over the side of the shelf 1.5 m above the ground (Figure 5-62). The system is released from rest at t = 0 and the 2.4 kg mass strikes the ground at t = 0.80 s. The system is now placed in its initial position and a 1.2 kg mass is placed on top of the block of mass m1. Released from rest, the 2.4 kg mass now strikes the ground 1.3 seconds later.


Figure 5.62
Determine the mass m1.
wrong check mark kg
Determine the coefficient of kinetic friction between m1 and the shelf.

 

[catkin]

The diagram? What you think are relevant equations? Your attempts at a solution?

 

[mjsd]

just posting a question like this without explaining your difficulties, what you have looked at etc, is unhelpful for yourself and ppl who may want to help