suppose you are sitting on a boat that is motion-less on the water, what happens when someone nearby tosses a watermelon, assuming you catch it? explain this according to the law of conservation of momentum
According to the law of conservation of momentum, the total momentum of an isolated system remains constant if no external forces act upon it. In this scenario, you are sitting on a motionless boat, making it an isolated system.
When someone nearby tosses a watermelon and you catch it, the watermelon adds momentum to the system. The law of conservation of momentum states that the total momentum before the interaction should be equal to the total momentum after the interaction.
Initially, both you and the boat have zero momentum since you are motionless. The watermelon, on the other hand, has some momentum due to the toss.
When you catch the watermelon, your body starts moving in the direction opposite to the watermelon's motion. To conserve momentum, the boat also needs to move in the opposite direction.
The watermelon's momentum is transferred to you, changing your momentum from zero to a non-zero value. Simultaneously, the boat gains an equal but opposite momentum to keep the total momentum of the system constant.
So, when someone nearby tosses a watermelon and you catch it, the boat will push back in the opposite direction to maintain the conservation of momentum. This reaction is commonly observed when objects are thrown in space, where the absence of external forces allows the law of conservation of momentum to hold true.
Luis answered below.
Momentum of watermelon/ boat system remains the same before and after
Momentum watermelon before + zero momentum of boat before = momentum of boat/watermelon sum after.