a 0.01 bullet is fired into a 2.5 kg pendulum bob initially at rest becomes embedded in it. after the collision, the pendulum rises a vertical distance of 0.8m. calculate the initial speed of the bullet

A., d., and f i think

Protons have a positive charge and, collectively, give an element its atomic number.

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.