Question

Two groups of canoeists meet in the middle of a lake, shown to the right. A person in canoe 1 pushes on canoe 2 with a force of 63.0 N to separate the canoes. If the mass of canoe 1 and its occupants is 150 kg., and the mass of canoe 2 and its occupants is 280kg, find the following quantities after 2.50 s of pushing. (Neglect the friction force between the canoes and the water. The + direction is to the right). (NOTE: Do NOT use Newton's 2nd Law or a Kinematic Equation to solve problem.) a) The momentum and velocity of canoe 1: Linear Momentum =? Velocity=? b) The momentum and velocity of canoe 2: Linear Momentum =? Velocity=?

Answer 1

According to newton's third law,

action force = - reaction force

i.e F1= -F2 ------------- (1)

The acceleration canoe1 = F1/M1

a1 = 63/150

a1= 0.42 m/s^2

now for the speed

use the kinemat9ic equation

V = u+at -------------- (2)

V = at

V1 0.42*2.50

V1 = 1.05 m/s

The acceleration canoe2 a2 = F2/M2

a2 = 63/250

a2 = -0.252 m/s^2

The speed of the canoe2, V2 = at

V2 = -0.252*2.50 =- 0.63 m/s

A) the momentum of the canoe1 = 150 *1.05 = 157.5 kg.m/s

part B:

the momentum of the canoe2 = -280* 0.63

P2 = -176.4 kg.m/s