# Newton's Laws of Motion : Block Problem

rajumahtora

## Homework Statement

In the arrangement shown, all surfaces are frictionless, mass of block M = 30 kg and m = 20 kg.
If F = 180 N , Find accelerations of both the blocks

2. Doubt

What amt of force will act on larger block M, just T(coz of horizontal string around the pulley) or 2T(coz of both the strings around the pulley)

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Jilang
Imagine that the pulleys were not attached to anything else except the string. In which directions do you think they would be pulled?

Homework Helper
hi rajumahtora!

when you consider the forces on a body, you must consider the whole body …

the block M is attached to the pulleys, so you must consider the external forces on the block-plus-pulleys

Homework Helper

## Homework Statement

In the arrangement shown, all surfaces are frictionless, mass of block M = 30 kg and m = 20 kg.
If F = 180 N , Find accelerations of both the blocks

2. Doubt

How much force will be applied on the larger block M by the pulley(coz of tension)?
1. T towards right
2. T towards up
3. T√2 45° to the right

3.Reason for doubt

If the total for exerted on the T i(cap) + T j(cap) i.e. Fnet on Bock M due to tension of string on pulley is T√2,
then there will be a force which will tend to pull block M upward...and if the accln of string is much higher, then the tension in the string will cause the block to accelerate up.

[To Jilang and tiny-tim,