Cold temperature can't "flow" into a warmer object, in this case, the person's hand. The heat energy of the hand gets transferred to the colder object, the ice.
To act as the Sun' was accepted but if you put 'sunlight' alone it was not accepted. The examiner wanted you to state that the infra red radiation was needed to warm up the water.
GPE = mgh (for objects close to earth where g can be considered to be constant) Where m is the mass, g is the acceleration due to gravity (which the question has told us to assume is 10ms^-2), and h is the height of the object.
Substituting the values in:
GPE = 70*10*10 = 7000J
Answer: A
Explanation: the principle of friction with swinging and colliding balls.
