Amogh Gajare
Last Activity: 9 Years ago
Hello.U
i = -

R
2g

.....................that’s the formula which is used in these kind of problems.Lambda represents mass per unit length,R is radius,g is 10 m/s
2.Upper limit is taken as 90 degree as quarter cicle is given in question and lower limit is obviously 0 degree as it is becoming horizontal finally.
Therefore U
i = -

R
2g (After solving integration)............let us label it
equation 1But

=

as circumference representing the beads is 1/4th circle.
So when we substitute

value in
equation 1 we get,U
i =

R is also height here.So the final potential energy Uf = -mgR (Negative sign because of opposite direction.)
So work done by gravity = Ui – Uf

+ mRg = mRg(1 –

)
And by work energy theorem W = change in kinetic energy
mRg(1 –

) = ½ m

– 0
So after solving we get

So answer will be square root of whole of the term mentioned above.