Using Snell's Law
Material
Index of Refraction
An incident ray strikes a boundary at a 72.5-degree
angle, resulting in an angle of refraction of 39.6
degrees. The index of refraction of the first medium is
1.0003
What is medium 1?
Air
1.0003
Water
What is medium 2?
Water
Quartz
Lucite
1.33
1.46
1.50
150
Zircon
1.92
Diamond
2.42
Intro
Done

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.