Homework Solution

TP 2-8

Given:

        m = 20 kg
        v_i = 0 (at rest)
        F_net = 40 N
        d = 5 m
        no heat losses
        flat surface

Find:

        KE_f and  v_f

Science:

        W = F d

        KE = (1/2)mv²

        W = D(KE + PE)

Solve:

        W = DKE = (40 N)(5 m) = 200 J

        KE_f  = W + KE_i = 200 J + 0 = 200 J

        v_f =[(2)KE_f /m]^1/2 = [(2)(200 J)/(20 kg)]^1/2 = 4.47 m/s