Arock at the top of a 30 meter cliff has a mass of 25 kg. calculate the rock’s gravitational potential energy when dropped off the cliff. assuming that energy is conserved and there is no air friction and gravity is 9.8 m/sec., at the bottom of the cliff the rock’s potential energy is completely converted to kinetic energy. use the formula for kinetic energy to calculate the rock’s speed at the bottom of the cliff. show all calculations.

Lets see:-

We have our formula for potential energy, which we are trying to solve for, 

PE = mgh  or  potential energy = mass * gravity * height

So we know that PE all depends on these. 

Height :  30 meters
Mass : 25 kg
Gravity (which is always constant) : 9.8 m/s/s

Now add into formula. 

PE = 25*30*9.8 
PE = 7350 Joules

PE = 7350 Joules

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.