Apole vaulter runs forward, plants his pole, rises in the air and lands. what point represents his greatest amount of gravitational potential energy?

At the maximum height of the vault  

Explanation:

The formula for gravitational energy (GPE) is

GPE = mgh, where

m = the pole vaulter's mass

g = the acceleration due to gravity

h = the height above the ground

Since m and g are constant,

GPE ∝ h

The point of highest GPE is at the maximum height of the vault, just before he starts falling towards the ground.

b. th3 n4zc4 pl4t3 15 c0nv3rg1ng w1th the s0uth 4m3ric4n pl4t3.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol