A car starting from rest accelerates at a rate of 8.0 m/s/s. What is it’s final speed at the end of 4.0 seconds?

vf = 32 m/s

Explanation: Solution:

Use the formula for acceleration:

a = vf - vi / t

initial velocity vi = 0 since it is at rest.

derive to find vf:

vf = at + vi

   = 8.0 m/s² ( 4.0 s ) + 0 m/s

   = 32 m/s

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.