Answer:
0.82 m/s
Explanation:
From the law of conservation of momentum,
Total momentum = Final momentum.
mu+m'u' = V(m+m')......................... equation 1
Where m = mass of Lillian, u = initial velocity of Lillian before she catches the dog, m' = mass of the dog, u' = initial velocity of the dog, V = velocity of Lillian and the dog.
make V the subject of the equation,
V = (mu+m'u')/(m+m')................ Equation 2
Given: m = 40 kg, m' = 15 kg, u = 0 m/s (Lillian was standing at rest), u' = 3.0 m/s.
Substitute into equation 2
V = (40×0+15×3)/(40+15)
V = (0+45)/55
V = 45/55
V = 0.82 m/s
