Question #125628

.Three ballot boxes are connected by cords, one of which wraps over a pulley having negligible friction on its axle and negligible mass. The three masses are mA=30Kg, mB=40Kg and mC=10Kg . Determine the tension in the cord connecting B and C when the assembly was released. ii. How far does A move in the first 0.25 s (assuming it does not reach the pulley)?

Expert's answer

The tension in the cord connecting B and C when the assembly was released is the weight of C. To find the weight, we must find the acceleration of the system.

Direct x-axis to the right, y-axis upward. Write Newton's second law for box A:

We can consider the hanging boxes B and C as one body since the cord is non-inextensible. Therefore, Newton's second law for them looks like

Therefore, the tension between B and C is

To answer how far A goes in the first 0.25 s, all we need is to use this simple equation:

Learn more about our help with Assignments: MechanicsRelativity

## Comments

## Leave a comment