Vertical Circular Motion
Roller Coaster
Roller Coaster
Twirling a Ball on a String Vertically x mg T T mg maR T = 0; vcr mg maR T cannot be negative, the bob will fall down! mg maR
Non-uniform Circular Motion If an object is moving in a circular path but at varying speeds, it must have a tangential component to its acceleration as well as the radial one.
Ferris Wheel
Sustained vertical spinning Ever wonder what a bike tire feels like? At constant speed, the centripetal acceleration is constant (v2/r), but the direction of gravity keeps changing! Feel heavier at bottom than at top This ride definitely turns your world around!
Bucket of Water NB,W water a WE,W
Bridges & Speed Bumps The curvature of the bridge/bump and your speed determines if you are going to stay on the bump (N>0) or if you are going to bump: fly off it!
How fast do you need to drive to leave the ground?
Connected Bodies Two different masses (m < M) are connected by a string going through a tube. Predict what will happen when you whirl the lighter mass with constant but high speed. Base your prediction on the CM model. m M Mass M will be falling down since it is heavier Mass M will be moving up and then stop Mass M will move up and then will fall down It is impossible to whirl the lighter mass around
Connected Bodies - Analysis q m M T mg x y If the mv2/R is > Mg, the mass M will accelerate upwards. Notice, the mass m will always rotate so the string is not horizontal. It happens so T has a vertical component to cancel out the mg!
Satellites in Circular Orbits
Weightlessness in Space Shuttle
Artifical Gravity