Question

Question in attachment. its a mechanics question.
Show ur working please. thnx

Answer 1

@Mashy :P

Answer 2

you mean what MINIMUM downward force :P

Answer 3

well.. take the moments and forces.. and equate them to zero

Answer 4

yes

Answer 5

tried and failed

Answer 6

Lets solve it seperately.
consider the force at P is x

then you can measure what will be the force at the other end of the level..lets say y

so now consider the slab

on the slab.. there is an upward force y at one end
there is its own weight downward
and two reactions forces upwards..

so you considered all these?! show your calculatoins!

Answer 7

and why is this in math forum? :P

Answer 8

where should it be ?

Answer 9

mechanics is one of the modules in maths course

Answer 10

physics forum.. but its ok.. lets stick here itself :P

Answer 11

wow really!? :-/.. its usually taught in physics!

Answer 12

I had the option to choose stats or mechanics so I chose mechanics

Answer 13

because, u are right, its in physics as well

Answer 14

I have never encountered a question like this before so can u show me the working please

Answer 15

lets do it step wise.. i won't solve it.. :P.. but ll only help you

lets consider the lever!.. now the lever is light.. so you don't have to worry about its weight..

if you apply a force x at the end X of the lever.. what force will come at end P ??
you have to use moments!! can you do it!?

Answer 16

i mean what force will come at the end Y .. the other end of the lever?!

Answer 17

P*1.25 is that correct ?

Answer 18

nope .. its not a force multiplier.. check properly.. the net moment about the fulcrum must be zero!

Answer 19

upward force at y = P*1.25/0.25 ?

Answer 20

i mean the moment on both sides should be equal :P

Answer 21

tell me what is the moment of P about the fulcrum!?

Answer 22

P*1.5 ? correct ?

Answer 23

sorry P*1.25 ?

Answer 24

anticlocwise

Answer 25

yea correct..

now if there was a force Q on the other side.. what would be the moment of that force about the fulcrum!?

Answer 26

Q*0.25 clockwise

Answer 27

precisely.. now if the lever were to be in equilibrium.. the two forces should be equal..

so equate and you would get what is Q

since there is no REAL force Q acting downwards.. it would mean that the Q amount of force is actually acting upwards ..

Answer 28

i mean't the two moments should be equal.. i think i am high today :-/

Answer 29

we don't know P, we don't know Q. How am going to find a value for P

Answer 30

no no.. i mean find Q in terms of P !

Answer 31

Q = P*1.25/0.25 correct ?

Answer 32

correct.. :)..

so now this is the upward force that is acting at the end A of the slab..

other upward forces which are acting are reaction forces at C and D.. lets call the Rc and Rd.. however reaction at c should be zero.. so Rc = 0

and we have its own weight 1000g acting downward at its centre of mass ..

so the net force must be zero.. can you develop an equation consider these?!? NET FORCE (not moments).. must be zero!

Answer 33

lol where you go!? :-/