A ball is thrown horizontally from the top of s vertical tower and strikes the ground at point 50m from the bottom of the tower. Given that the height of the tower is 45m, determine the a)time taken for the ball to hit the ground
b)the initial horizontal velocity of the ball
c)The vertical height of the ball just before striking the ground(take acceleration due to gravity as 10m/s)​

An ionic compound can conduct electricity when a it is dissolved in water b its crystals are ground into powder c it is in solid form d it is heated to just below its melting point

4.at 0 ºc, some amount of energy is required to change 1 kg of water from a solid into a liquid. if you had a 2 kg piece of ice, what effect would this have on the amount of thermal energy required to change the water from a solid to a liquid? it would require more energy to change solid water into liquid water because there are more molecules in this larger piece of ice. it would still require the same amount of energy to change solid water into liquid water because the entire piece of ice would still gain the same amount of energy in each case. it would require energy to be removed from the 2 kg piece of ice. the larger piece of ice already has more total energy than the smaller piece of ice, so energy must be removed for the ice to become liquid. it would require less energy to change solid water into liquid water because the energy would spread through the ice more quickly and the ice already has a larger total amount of energy because it is larger than a 1 kg piece of ice.

When and why was the metric system invented?