calculate the mass of an object attached at the end of the rope 7.5m long suspended from a fixed support and made to swing.suppose the speed of the object at its lowest point of the swing is 3m/s and the tension in the rope at the lowest point is 495N

centripetal acceleration = v^2/r

= 9/7.5 = 1.2 m/s^2

weight down = 9.81 m

tension up = 495

so
495 - 9.81 m = m (1.2)

495 = m (11.01)

m = 45 kg