Under what condition will a car skid on a leveled circular road?

Identify the forces acting on blocks A, B and C shown in the figure

Apply Newton's second law to a mango hanging from a tree. (Mass of the mango is 400 gm).

Consider a horse attached to the cart which is initially at rest. If the horse starts walking forward, the cart also accelerates in the forward direction. If the horse pulls the cart with force F_h in forward direction, then according to Newton's third law, the cart also pulls the horse by equivalent opposite force F_c = F_h in backward direction. Then total force on 'cart+horse' is zero. Why is it then the 'cart+horse' accelerates and moves forward?

A block of mass m is pushed momentarily along a horizontal surface with an initial velocity u. If u_k is the coefficient of kinetic friction between the object and surface, find the time at which the block comes to rest.