Level 1: A Boat on the Moon: Does It Float Higher?
A ball held under water, in a lift.
A wooden ball is held completely under water by a thread tied to the bottom of a bucket; the thread's tension is T. The bucket is put in a lift accelerating upward at g/2. The tension becomes:
The thread holds the ball down against the net upward push, the buoyancy minus the weight. In the lift, both the buoyancy and the weight are set by the effective gravity g + a.
The tension rises to 1.5T. A floating boat's depth does not depend on g, because only a balance of forces is involved, but the size of an unbalanced force such as this tension does.
Every Level 2 starts from a quick question, Level 1, and changes one thing. Seeing what that change does is the skill JEE Main tests. Try it here, free and with no signup, then read the worked answer.
