My 2 yo was in front of shopping cart. bros jumped on cart & knocked it forward to ground. don't think he hit head or very lightly. no crying. worry?

Generally no concern: Most of the time if a child hits himself against an object, falls on a hard surface and the like just observe your child. Of course, settings and children are different. Generally if no loss of consciousness, child is herself/himself, then just observation should be enough. However, if the child shows any odd behivior, then an emergency evaluation would be wise. Most importantly remain calm!