A body of mass 2 kg is thrown up vertically with K.E of 490 joules If the acceleration due to gravity is 9.8 m/s2 the height at which the K.E of the body becomes half its original value is give by:
Two points charges A and B separated by a distance R attract each other with a force of 12 x 10-3 N. The force between A and B when the charges on them are doubled and distance is halved