The Total solution for NCERT class 6-12
Youmay have seen in a circus a motorcyclist driving in vertical loops inside a‘death-well’ (a hollow spherical chamber with holes, so the spectators canwatch from outside). Explain clearly why the motorcyclist does not drop downwhen he is at the uppermost point, with no support from below. What is theminimum speed required at the uppermost position to perform a vertical loop ifthe radius of the chamber is 25 m?
Ina death-well, a motorcyclist does not fall at the top point of a vertical loopbecause both the force of normal reaction and the weight of the motorcyclistact downward and are balanced by the centripetal force. This situation is shownin the following figure.
The net force acting on the motorcyclist isthe sum of the normal force (FN) and the force due to gravity(Fg = mg).
The equation of motion for the centripetalacceleration ac, can be written as:
Fnet = mac
Normal reaction is provided by the speed ofthe motorcyclist. At the minimum speed (vmin), FN =0