- #1
Kernul
- 211
- 7
Homework Statement
A block of 100g is attached to a wire inexstensible long 50cm. The block is left with a null initial velocity when the wire form an angle of 90° with the vertical. Calculate the velocity of the block and the tension of the wire when the block is at the position of equilibrium. Also calculate the velocity of the block when it forms an angle of 30° with the vertical after the position of equilibrium.
Homework Equations
The Attempt at a Solution
I started by calculating the velocity of the block at the position of equilibrium.
I used the law of conservation of mechanical energy and so:
K0 = 1/2 * m * v02 = 0
because the initial velocity is zero.
U0 = 0
K = 1/2 * m * v2
U = - m * g * l
So we have
0 =1/2 * m * v2 - m * g * l
v = sqrt(2 * g * l) = 3.13 m/s
After this I should calculate the tension of the wire too but I don't get how to do it.
I tried doing this:
{m * ax = - T sin90° = - T
{m * ay = T cos90° - P = - P = m * g
But beside this I don't know how to proceed.
Can someone help me how to do this little part?