Whenever there is a change of state, such as a solid to liquid or liquid to gas, heat energy can be added without a temperature change because a) the added energy is not needed. b) the energy is lost to the system. c) the change of state requires energy. d) the energy is lost to the atmosphere. 11) which would be best categorized as heat transfer by convection? a) wearing a white shirt to stay cool on a summer day. b) noodles rising and falling in a pot of boiling water c) touching a metal spoon that is sitting in a pot of boiling water d) using a heating blanket to get warm

the velocity you are looking for is made up of two parts: horizontally velocity, vh, and its vertical velocity, vv. the actual velocity of the ball will be these two parts added together, and because velocity is a vector then they will need to be added vectorially.  

neglecting air resistance etc etc.,  

the horizontal velocity component will be constant (because there is no accelerating force in the horizontal direction.  

vh = 8 ms-1  

the vertical velocity component has an accelerating force: 'g'.  

using v = u +at where a = g = 9.81 ms-2.  

the vertical component of velocity, vv = 0 + gt = vv =9.81 x 2  

vv = 19.62 ms-1 . the zero appears because the virtical component of velocity at time t=0 is zero. remember, the ball was thrown horizontally.  

how fast it will be moving (it actual path (being a parabola )) will be the vector sum of these two.  

adding vectorally gives: -  

v = sqr root (8^2 + 19.62^2) = sqr root(64+384.9) = 21.18 or 21.2 ms-1