A block of mass m is placed on a block of mass 2m. The lower block rests on a smooth floor. Coefficient of static friction between blocks is μ. A horizontal force F is applied to the upper block. The friction required to make the blocks move together is 4μmg/3. Which statement is correct?
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Question

A block of mass m is placed on a block of mass 2m. The lower block rests on a smooth floor. Coefficient of static friction between blocks is μ. A horizontal force F is applied to the upper block. The friction required to make the blocks move together is 4μmg/3. Which statement is correct?

Options

G1 Physics · Accepted Answer

For no relative motion, static friction cannot exceed fₘₐₓ = μmg. Here the friction required for common motion is 4μmg/3, which is greater than μmg. Therefore static friction is insufficient and slipping must occur.