in the apparatus shown above, one end of a string of length L is attached to a block of mass M and the other is connected to the axle of a motor that rotates, causing the block to move in a circle of radius R at a constant speed vt such that the string makes an angle 0 with the vertical. A student wants to use the apparatus to make measurements and create a graph that can be used to estimate the acceleration g due to gravity at the surface of Earth. The student can adjust the motor to achieve different tangential speeds of the block.