Two masses of 60 N & 30N are positioned over frictionless & massless pulley (fig.) If the 60 N. mass is released from rest, find the speed at which the 60N mass will hit the ground.

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written 8.2 years ago by

teamques10 ★ 69k

modified 3.2 years ago by

pedsangini276 • 4.8k

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Mumbai University > FE > Sem 1 > Engineering Mechanics

Marks : 04

Years : MAY 2015

engineering mechanics

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1 Answer

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written 8.2 years ago by

teamques10 ★ 69k

For block A

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$∑Fy = m\space a_y$ (D Alembert principle)

$T – 30 = (30/9.8) a \\ T – 3.06 a = 30 ….i$

For block B

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$∑Fy = m\space a_y$ (D Alembert principle)

$T – 60 = -(60/9.8) a \\ T + 6.12 a = 60 ….ii$

Solving I and ii

$T = 40N \\ . a = 3.27 m/s^2$

Using third kinematical equation

$V^2 = u^2 + 2as \\ V^2 = 0^2 + 2\times 3.27 \times 2 \\ V = 3.62 m/s$

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