Question

A body of mass 10 kg is placed on a table. Find the
force required to move the body, if coefficient of
friction be 0-20.

​

Answer 1

There is minimum a magnitude of forces required, both in horizontal and vertical direction, either to slide or lift up the block. The block will first slide or lift up would depend upon which minimum magnitude of force is lesser.

For block to start lifting up, in vertical direction

Fsin37

∘

+N−Mg≥0

N becomes zero on just lifting condition.

F

lift

≥

3/5

10g

∴F

lift

≥

3

500

N

For horizontal direction to start sliding

Fcos37≥μ

s

N

Fcos37

∘

>0.5[10g−Fsin37

∘

](∵N=10g−Fsin37

∘

)

Hence f

slide

>

cos37

∘

+0.5sin37

∘

50

f

slide

>

11

500

N

F

lift

>

3

500

N

⇒f

slide

<F

lift

Therefore the block will begin to slide before lifting.

Answer 2

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