1) A rock of mass 1.50kg is released from rest at a height of 30m. Ignore air resistance and calculate;
(a) its speed half way down
(b) its speed on reaching the ground
(c) its total mechanical energy
(i) at a height of 30m
(ii) its kinetic energy half way through
(iii) its potential energy on striking the ground

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 

Because the sun is the biggest and if the sun orbits the earth we will be dead probably

Answer ( slope);