A particle of small mass m is joined to a very heavy body by a light string passing over a light pulley. Both bodies are free to move. The total downward force in the pulley is

Question

A particle of small mass m is joined to a very heavy body by a light string passing over a light pulley. Both bodies are free to move. The total downward force in the pulley is (A) mg (B) 2 mg (C) 4 mg (D) can not be determined

Tardigrade Admin · Accepted Answer

T - mg = ma ...(1) Mg - T = Ma ...(2) from (1) and (2) a =(( M - m / M + m )) g Put M >> m ⇒ a = g ∴ T =2 mg, 2 T =4 mg <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/e0754d8f94b285e2032a8b8390dfe426-.png" />

Q. A particle of small mass m is joined to a very heavy body by a light string passing over a light pulley. Both bodies are free to move. The total downward force in the pulley is

mg

2 mg

4 mg

can not be determined

$T - m g = ma$ ...(1)
$M g - T = M a$ ...(2)
from $(1)$ and $(2)$
$a = (\frac{M - m}{M + m}) g$
Put $M >> m$
$\Rightarrow a = g$
$∴ T = 2 m g,$
$2 T = 4 m g$

Q. A particle of small mass m is joined to a very heavy body by a light string passing over a light pulley. Both bodies are free to move. The total downward force in the pulley is

mg

2 mg

4 mg

can not be determined

T−mg=ma ...(1) Mg−T=Ma ...(2) from (1) and (2) a=(M+mM−m​)g Put M>>m ⇒a=g ∴T=2mg, 2T=4mg

$T - m g = ma$ ...(1)
$M g - T = M a$ ...(2)
from $(1)$ and $(2)$
$a = (\frac{M - m}{M + m}) g$
Put $M >> m$
$\Rightarrow a = g$
$∴ T = 2 m g,$
$2 T = 4 m g$