It takes some work for you to lift an object 20cm. How much work must you do to lift the same object 40cm?

Twice the work needed to lift the 20cm object

Explanation:

Work done is derived using the expression below;

  Work done  = Force x distance

For this problem, we are lifting through a vertical height;

  Work done  = mg x h

 mg is the weight of the body;

Since both bodies have the same weigh;

   W1 is the workdone to lift 20cm

   W2 is the workdone to lift 40cm

   For the first lift;

         W1  = (mg) x 20cm

         (mg)  =  

   For the second lift;

          W2  = (mg)  x 40cm

   Since they both have the same weight

          (mg)  =  

Equating the two weights;

        =    

     20W2  = 40W1

          W2  =   = 2W1

c, 1a hope this

power out to power in less than 100%