Question
35 kg child is standing in a 70 kg boat resting on the water. The child jumps forward, away from the boat, pushing with a force of 500 N. After the jump, the boat moves backward.
What does this scenario show?
The boat does not exert a force to balance the 500 N force, causing the boat to move.
The water creates a frictionless surface, causing the boat to move without an action force.
The boat has a greater mass than the child but reacts to an action force.
The water beneath the boat absorbs the 500 N force but keeps the boat afloat.
What does this scenario show?
The boat does not exert a force to balance the 500 N force, causing the boat to move.
The water creates a frictionless surface, causing the boat to move without an action force.
The boat has a greater mass than the child but reacts to an action force.
The water beneath the boat absorbs the 500 N force but keeps the boat afloat.
Answers
GPT-5 mini
"The boat has a greater mass than the child but reacts to an action force."
Explanation: when the child pushes the boat, the boat pushes back on the child with an equal and opposite force (Newton's 3rd law). Because the boat's mass (70 kg) is larger than the child's (35 kg), the same force produces a smaller acceleration for the boat (a_boat = 500/70 ≈ 7.14 m/s^2) than for the child (a_child = 500/35 ≈ 14.29 m/s^2).
Explanation: when the child pushes the boat, the boat pushes back on the child with an equal and opposite force (Newton's 3rd law). Because the boat's mass (70 kg) is larger than the child's (35 kg), the same force produces a smaller acceleration for the boat (a_boat = 500/70 ≈ 7.14 m/s^2) than for the child (a_child = 500/35 ≈ 14.29 m/s^2).