00:01
Okay, so it's actually a physics problem, not chemistry problem, right? so it says a two kilograms object rolls down an incline of 20 meter high at the speed of the 5 meter per seconds.
00:22
So in this case, it says, right, initially you have the object where scroll down for incline, right? so it's like this, the object is here.
00:40
So it tells you initially the v0 is a 5 meter per second.
00:52
And initially it's located at a height at about 20 meters.
01:02
So once it reach the bottom, right, there's another actually a ramp, right, another ramp and inclined as 30 degree.
01:15
So no doubt, right, once you reach the bottom, the board again goes to the up.
01:28
So find the speed as a bottle of the incline.
01:31
So we want to know at this point, what is the speed? so from here, usually the easiest way to solve that is to use the balance of the energy.
01:50
That means, right, all the energy.
01:53
So here in this case, right, there's a gravity potential was released.
01:59
And the gravity potential was transformed to the kinetic energy.
02:03
So we could build a equation that is the change of the kinetic energy, ek, equals to the change of the gravity potential.
02:15
So in this case, the gravity potential in this case is released, right? oh sorry, here usually i think most common ways the change should be equal to zero, right? so the change of the kinetic energy, what's the change of the kinetic energy? so that's equals to the final kinetic energy minus the initial kinetic energy.
02:51
And the change of the potential here, so it's a release, right? so the potential is decreased.
03:00
So that's equal to the minor selling, the gravity force.
03:07
It's m g times h equals to 0 so in this case it tells you the initial right the initial the final kinetic energy is one half the mass times vt square minus one half m v0 square equals to the mass times the gravity constant times h so in this case we can write down to the vt square, right? so the m can be canceled.
03:43
So it becomes vt square minus v0 square equals to two gravity g.
03:51
So the vt square, we don't know, equals to 2gh plus v0 square.
04:00
So the g is usually we use 9 .8...