Why would normal force be set to zero to calculate the minimum possible speed a rider can have at the top of a loop.
Please i need help, this is due in few hours
To calculate the minimum possible speed a rider can have at the top of a loop, we need to consider the forces acting on the rider at that point. In this case, the two main forces are gravity and the normal force.
The normal force is the force exerted by a surface to support the weight of an object resting on it. In the case of a loop, the normal force acts perpendicular to the surface of the loop and provides the necessary centripetal force to keep the rider moving in a circular path.
When the rider reaches the top of the loop, the normal force is directed downwards (opposite to gravity). This is because the rider is upside down, and the surface of the loop is pushing the rider towards the center of the circular path. At the top, the net force (the vector sum of all forces) acting on the rider should provide the necessary centripetal force to keep the rider moving in a circular path.
To find the minimum possible speed, we assume that the normal force is zero. This leads to a situation where the weight of the rider is the only force acting, providing the necessary centripetal force. By setting the normal force to zero, we are effectively assuming that the rider is not in contact with the loop (i.e., the loop is frictionless) at the top, which allows us to calculate the minimum speed required.
To summarize, setting the normal force to zero at the top of the loop allows us to isolate the effect of gravity alone and find the minimum speed necessary for the rider to stay on the loop.