An object of mass m, attached to a light cord of length L, is held horizontally from a fixed support as shown in Fig 1. The object is then
released from rest. What is the tension force in the cord when the object
is at the lowest point of its swing?

On a frictionless air track, a blue glider with mass 0.200 kg is moving to the right with a speed of 8.00 m/s. it strikes a red glider that has mass 0.600 kg and that is initially at rest. after the collision, the blue glider is moving to the left with a speed of 3.00 m/s.(a) what are the magnitude and direction of the velocity of the red glider after the collision? (b) is this collision elastic?