Question

You may have seen in a circus a motor cyclist driving in vertical loops inside a 'death well' (a hollow spherical chamber with holes, so the spectators can watch from outside). Explain clearly, why the motorcyclist does not drop down when he is at uppermost point, with no support from below. What is the minimum speed required at the uppermost position to perform a vertical loop if the radius of the chamber is 25 m?

Answer 1

At the upper point of the loop, the equation can be given as R + mg = mv²/r   ...(i)

Where R is the normal reaction and 'r' is the radius of the loop. Minimum possible speed at the uppermost point is when R = 0

∴ Equation (i) becomes, mg = mv²/r

v_min = √{rg} = √{25 x 10} = 15.8 ms^-1