Question

A weightlifter uses a force of 356 N to lift a set of weights 2.2 m off the ground. How much work did the weightlifter do? Answer:

Answer 1

783.2 N.m or Joules

Step-by-step explanation:

`W=F*d*cos(Ф)`

Work done when a force F is applied to move an object by a displacement d meters

where cos(Ф) is the angle between applied force F and displacement d

Since the weightlifter is applying the force upward and the set of weight also move upward therefore, both are in same direction hence angle will be zero.

Now lets substitute the given values into the work equation:

`W=356*2.2*cos(0)`

since cos(0)=1

`W=356*2.2*1`

`W=783.2 N.m`

or

`W=783.2 Joules`

Since the unit of Force is Newton (N) and the unit of displacement is meters (m) therefore, unit of work done will be N.m

Note: 1 N.m is equivalent to 1 joule