Consider two vectors P⃗ =7.5i^ and Q⃗ =−1.5i^+6.0j^. If another vector R⃗ =P⃗ +Q⃗ , what is the magnitude of R⃗ ?

The speed was not exceeded so it was slow

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.