an athlete is working out in the weight room. he steadily holds 50 kg above his head for ten seconds which statement is true about this situation.
1 the athlete isn't doing any work because he doesn't move the weight.
2 the athlete isn't doing any work because he doesn't hold the weight long enough.
3 the athlete is doing work because he prevents the weight from falling down.
4 the athlete is doing work because 50 kg is a significant load to lift.