Muscular strength is the ability of the blank to exert force during an activity?

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

Simple machines can a. increase force only b. decrease force only c. increase or decrease force