# A ball weighing 0.4 kg is suspended from a smooth vertical wall on a thread.

**A ball weighing 0.4 kg is suspended from a smooth vertical wall on a thread. Determine the thread tension if it is at a 60-degree angle with the vertical.**

m = 0.4 kg. g = 9.8 m / s ^ 2. ∠α = 60 “. N -? The force of gravity m * g, which is directed vertically downward, is balanced by the tension force of the thread N, which is directed along the thread. Since the thread is directed at an angle ∠α = 60 to the vertical, then the tension force of the thread is also will make an angle ∠α = 60 “with the vertical. The projection of the thread tension force on the vertical axis Ny will be determined by the formula: Ny = N * cosα. Ny = m * g. N * cosα = m * g. N = m * g / cosα. N = 0.4 kg * 9.8 m / s ^ 2 / cos60 “= 7.84 N.

Answer: the tension force of the thread is N = 7.84 N.