 Mathematical and Physical Journal
for High Schools
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# Problem P. 4662. (October 2014)

P. 4662. The goal-keeper is just about to kick off the ball. The kick lasts for $\displaystyle \Delta t=0.01$ s, during which the goalkeeper exerts an average force of $\displaystyle F=850$ N on the ball lying on the ground. If there is no air drag, the kicked ball would reach the ground in $\displaystyle t=3$ s and it would be $\displaystyle \ell=45$ m further.

$\displaystyle a)$ What is the greatest height that the ball could reach?

$\displaystyle b)$ According to the official rules of association football the mass of the ball must be between 410 g and 450 g. Is the match played according to the rules?

(4 pont)

Deadline expired on November 10, 2014.

### Statistics:

 154 students sent a solution. 4 points: 122 students. 3 points: 10 students. 2 points: 13 students. 1 point: 6 students. 0 point: 3 students.

Problems in Physics of KöMaL, October 2014