A soccer player practices kicking the ball into the goal from halfway down the soccer field. The time it takes for the ball to g
et to the goal from the time it is kicked averages about three seconds. The soccer field is 90 meters long. The player wants to know the average velocity of the ball. Is there enough information to calculate this? A) No, only average speed can be calculated from the distance of 90 meters and the time of three seconds.
B) Yes, displacement is 45 meters, elapsed time is three seconds, and the direction is toward the goal.
C) No, only average speed can be calculated from the distance of 45 meters and the time of three seconds.
D) Yes, displacement is 90 meters, elapsed time is three seconds, and the direction is toward the goal.
The closer the particles get, the stronger the Coulomb force, which elongates choices C and D. The Coulomb force is inversely proportional to the distance squared. If the distance is cut in half, the force is multiplied by the reciprocal of (1/2)^2, which is 4. Multiplying it out, 20 times 4 is 80 N.
