Question

A mass of 4.83 kg is suspended from a 1.91 m long string. It revolves in a horizontal circle. If the string makes an angle of 56.9 degrees with the vertical, then what is the net force acting on the mass?

Answer 1

The net force acting on the mass in the vertical direction is zero since the mass is moving at a fixed angle of 56.9^o.

So, Tcos56.9= mg

=> T = (4.83 x 9.8)/cos56.9 = 86.676 N

the net force on the mass will be in the horizontal direction which will be responsible for its circular motion.

So, Tsin56.9 = F_net

=> F_net = 86.676sin56.9 = 72.610 N [answer]

this will be equal to the centripetal force.

F_net = F_c = mv²/r

=> 72.610 = 4.83v²/1.91

=> v = 5.3584 m/s. This will be the velocity of the mass on the string