A mass of M ~kg is suspended by a weightless string. The horizontal force that is required to displace it until the string makes an angle of 45^ with the initial vertical direction is

Step-by-step solution

Here, the constant horizontal force required to take the body from position 1 to position 2 can be calculated by using work-energy theorem. Let us assume that body is taken slowly so that its speed doesn't change, then aligned K & =0 & =W_F+W_ M g +W_ tension aligned [symbols have their usual meanings] aligned W_F & =F l 45^ , W_ M g & =M_g (l-l 45^ ), W_ tension =0 F & =M g( 2 -1) aligned