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A small block B is placed on block A of mass 5 kg and length 20 cm. A constant horizontal force of 10 N is applied to block A. If all surfaces are assumed frictionless and block B is at the right end of block A, then the time in which block B separates from A is:

A. 10 s
B. 1 s
C. 0.1 s
D. 0.01 s

User Givehug
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1 Answer

2 votes

Final answer:

With a horizontal force applied to block A, it will accelerate away from block B, which is on a frictionless surface. Block A, having a mass of 5 kg and being subjected to a 10 N force, will accelerate at 2 m/s². Block B will separate from block A after 0.1 seconds.

Step-by-step explanation:

The question involves a scenario where a small block B is placed on a larger block A on a frictionless surface. Considering that block A has a mass of 5 kg and a horizontal force of 10 N is applied to it, we need to determine the time it takes for block B to separate from block A. Since there are no frictional forces opposing this motion, block B will remain stationary relative to an observer on the ground as there's no force acting on it directly, while block A will accelerate and move out from under block B.

The acceleration of block A can be found using Newton's second law: a = F/m, where a is the acceleration, F is the force applied, and m is the mass. For block A, a = 10 N / 5 kg = 2 m/s². The time it takes for block A to move its own length of 20 cm (0.2 m) can be found using the kinematic equation: s = ut + 0.5at², where s is the displacement, u is the initial velocity (zero in this case), and t is the time. Solving for t we get t = √(2s/a), which means t = √(2*0.2 m / 2 m/s²) = 0.1 s. Therefore, the correct answer is 0.1 s.

User Paul McCabe
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