Two masses of 15.0kg and 20.0kg are connected by a light string that passes over a frictionless pulley

Question

a) Calculate acceleration of the system

b) Calculate the tension of the string

Answer 1

Mg - T = Ma; T - mg = ma

a) (M- m)g = (M + m)a; a = (M - m)g/(M + m); a = (20 - 15)g/(20 + 15) = g/7 = 1.4 m/s².

b) T = M(g - a) = 20kg(9.8 - 1.4)m/s² = 168 N