A car going at 20 m/s stops in a distance of 20 m. What is its deceleration?

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.

Answerit causes heavy precipitation for a short period of time