- #1
vxr
- 25
- 2
- Homework Statement
- A girl of mass ##m_{1} = 50## kg running with a velocity ##v_{1} = 5## m/s jumped into the boat of mass ##m_{2} = 150## kg. Determine a velocity ##v_{2}## at which a boat sailed away?
- Relevant Equations
- ##p = mv## and ##m_{1}v_{1} = m_{2}v_{2}## (I suppose)
Momentum of a girl:
$$p_{1} = m_{1}v_{1} = 50 * 5 = 250$$
Momentum of an idle boat:
$$p_{2} = m_{2}v_{2} = 150 * 0 = 0$$
So if the girl jumps into the boat, the two "systems" connect with each other. The momentum is passed onto the boat (?):
$$p_{1} = p_{2}$$
$$m_{1}v_{1} = m_{2}v_{2}$$
Substituting all known values:
$$250 = 150 v_{2}$$
$$v_{2} = \frac{5}{3} \quad \Big[ \frac{m}{s} \Big]$$
Does it look any good?
$$p_{1} = m_{1}v_{1} = 50 * 5 = 250$$
Momentum of an idle boat:
$$p_{2} = m_{2}v_{2} = 150 * 0 = 0$$
So if the girl jumps into the boat, the two "systems" connect with each other. The momentum is passed onto the boat (?):
$$p_{1} = p_{2}$$
$$m_{1}v_{1} = m_{2}v_{2}$$
Substituting all known values:
$$250 = 150 v_{2}$$
$$v_{2} = \frac{5}{3} \quad \Big[ \frac{m}{s} \Big]$$
Does it look any good?