Vežimėlis, riedėjęs horizontaliu paviršiumi 60 cm/s greičiu, susiduria su kitu vežimėliu, judančiu ta pačia kryptimi 180 cm/s greičiu. Po susidūrimo abu vežimėliai važiuoja ta pačia kryptimi vienodu 120 cm/s greičiu. Apskaičiuokite vežimėlių masių santykį.

The correct answer is  "c".  it is "c" because melting is an endothermic change, and endothermic get's energy from surroundings. 

That depends on what kind of environ meant it is in  in space it has the same force that was applied when the velocity was gained

Sublimation- which change of state is shown in model

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction