find the external force, acceleration of the two masses, find the tension of the rope of the two masses

Question

A block of mass 2.21753 kg lies on a friction- less table, pulled by another mass 3.08244 kg under the influence of Earth’s gravity. The acceleration of gravity is 9.8 m/s2 . What is the magnitude of the net external force F acting on the two mass system connected by the string? Answer in units of N.


What is the magnitude of the acceleration a of the two masses? Answer in units of m/s2.

What is the magnitude of the tension T of the rope between the two masses? Answer in units of N.

Answer 1

The mass on the table and the hanging mass can be considered as one mass of 2.21753+3.08244 = 5.29997 kg

This is acted upon by an external force, the weight of the hanging mass = (3.08244)8(9.8) = 30.20791 N

 

The acceleration can be found from Newton's second law F = ma, or a = F/m = 30.20791/5.299997 = 5.70 m/s²

 

The tension in the string is the force required to move mass on the table at the acceleration calculated above, so

T = ma = 2.21753*5.7 = 12.64 N