Mathematical and Physical Journal
for High Schools
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# Problem P. 4629. (April 2014)

P. 4629. An object is left to move along a horizontal surface, on which friction is not negligible. At one moment its kinetic energy is 900 J, and 2 s later it is only 400 J, while the object covers a distance of $\displaystyle \ell$.

$\displaystyle a)$ By what factor will the further distance until the object stops be greater than the distance $\displaystyle \ell$?

$\displaystyle b)$ How long does it take to cover this distance?

(4 pont)

Deadline expired on May 12, 2014.

Sorry, the solution is available only in Hungarian. Google translation

Megoldásvázlat. $\displaystyle a)$ 0,8-szorosát.

$\displaystyle b)$ 4 s alatt.

### Statistics:

 102 students sent a solution. 4 points: 72 students. 3 points: 11 students. 2 points: 8 students. 1 point: 10 students. 0 point: 1 student.

Problems in Physics of KöMaL, April 2014