a)
b)
Apply newton's second law
N = Wm + Wt
N = normal
Wm = weight of the man = mass of classmate *gravity= 65 kg * 9.8 m/s = 637 N
Wt = weight of the table = 500 N
N = 637 + 500 = 1,137 N
c) Weight = mass x gravity
Mass = Weight / gravity = 500 N / 9.8 m/s^2 = 51.02 kg