Question

You are standing in a boat. Which of the following strategies will make the boat start moving? Check all that apply.

Answer 1

Answer: Throwing some cargo out of the boa

Explanation:Pushing its mast, Pushing the front of the boat, Pushing another passenger are the forces in internal frame. Forces in the internal frame will not push the boat.  

Throwing some cargo out of the boat will create force in external frame of the boat. This external force will push the boat and boat starts moving.

Answer 2

Answer:

b. Throwing some cargo out of the boat

Explanation:

Using the Newton's third law of motion which states that every action has an equal and opposite reaction.

So when we are on the boat and we throw some mass in a direction away from the boat out of it then we are imparting the force to the floating boat by the law of conservation of momentum as well.

The relation can be mathematically expressed as:

$m_c.v_c=m_b.v_b$

where:

$m_c=$ mass of the cargo

$v_c=$ velocity of throwing the cargo

$m_b=$ mass of the whole boat including all that floats on it

$v_b=$ velocity of the boat system