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Question
A block of mass 2 kg placed on a long frictionless horizontal table is pulled horizontally by a constant force F. It is found to move 10 m in the first seconds. Find the magnitude of F.
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Solution
Given:
Mass of the block, m = 2 kg,
Distance covered, S = 10 m and initial velocity, u = 0
t = 2
Formula:
`S = ut + 1/2at^2`
F = ma
Solution:
Let a be the acceleration of the block.
`S = ut + 1/2at^2`
`10 = 1/2a(2^2)` (∵ u = 0)
∴ `a = (10 xx 2)/(2^2)`
∴ `a = (10 xx 2)/(2 xx 2)`
∴ `a = 20/4`
∴ a = 5
Force, F = ma
= 2 × 5
= 10 N
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