The acceleration perpendicular to the string (along a tangent to the circle) is given by resolving in this direction, and is simply .
The tension in the string is , since the lower mass is in equilibrium. So if we resolve along the string for the upper mass:2. A small block of mass m is placed on top of a frictionless table top. A light, inextensible string is threaded through a hole in the centre of the table and attached to the small block. The other end of the string is attach a large block of mass M which hangs below the table as shown. The small block is then made to move in a circle with radius r from the hole such that the large block remains suspended in equilibrium below. What is the expression for v, the speed of the small block given that there is a constant gravitational field, g.
Resolve vertically downwards:3. A ball of mass m is attached to the end of a piece of string. The ball is then given a kick such that it moves in a vertical circle of radius, r. If there is a constant, gravitational field g what is the downwards tension in the string when the ball is at the top of the circle given that at the top of the circle the ball is moving with a speed v?