The Input work on a pulley system is 75 J. If the pulley system is 84% efficient then what is the output work from the pulley system?

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

Who was the first scientist to measure speed as distance over time?

During which interval are the persons represented by the graph not moving? a) 0 to 0.5 hrs b) 1.5 to 2 hrs c) 2 to 2.5 hrs d) 4.5 to 5 hrs