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A stone of mass 2 kg is thrown with a velocity 5 m/s across the frozen surface of a lake and comesto rest after travelling a distance of 25 m. what is the force of friction between the stone and ice? |
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Answer» Answer: FORCE OF FRICTION = -4N Explanation: INITIAL VELOCITY of the stone, u= 20 m/s Final velocity of the stone, v= 0 Distance covered by the stone, s= 50 m We know the third equation of motion v²=u²+2as Substituting the known values in the above equation we get, 0² = (20)²+2(a)(50) -400 = 100a a = -400/100 = -4m/s² (retardation) We know that F = m×a Substituting above obtained value of a=-4 in F= m x awe get, F = 1×(-4) = -4N (Here the NEGATIVE sign indicates the OPPOSING force which is Friction) |
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