07_একাদশ শ্রেণী_পদার্থবিদ্যা_মহাকর্ষ - বস্তুর ওজন,জড়তা ভর ও মহাকর্ষীয় ভর
07_একাদশ শ্রেণী_পদার্থবিদ্যা_মহাকর্ষ - বস্তুর ওজন,জড়তা ভর ও মহাকর্ষীয় ভর
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00:00In Greek philosophy, Aristotle believed that the weight of an object is different depending on its stable and unstable position.
00:17It was believed that the weight of an object is divided into two parts.
00:21The stable part is the object's gravitational force and the gravitational force of the object's weight.
00:29Scientist Galileo did not agree with this theory.
00:33He proposed a scientific method that can measure the gravitational force of an object with the gravitational force of an object.
00:42Galileo proved that the gravitational force of an object is not the gravitational force of an object.
00:50Next is Newton's theory.
00:52Newton presented a simpler theory of weight and gravitational force.
00:57He divided the weight of an object into two parts.
01:01According to Newtonian theory, the weight of an object is related to the mass of the object.
01:10And the gravitational force of an object is related to the gravitational force of the object.
01:18For example, my weight is 72 kg.
01:23My weight is 72 kg.
01:26But my weight is less than the mass of the earth.
01:32So my weight is less than the mass of the earth.
01:36Similarly, my weight is 72 kg.
01:41But my weight is zero.
01:43Because there is no effect of the mass of the object.
01:47My weight is the mass of the object attracted by the gravitational force of the earth.
01:55So what is the relationship between weight and gravity?
01:58The gravitational force of an object attracted by the gravitational force of the earth is called the weight of the object.
02:06In other words, the weight of an object is equal to the gravitational force of an object.
02:16For example, the mass of an object is M.
02:19The gravitational force of an object attracted by the gravitational force of the earth is equal to F is equal to capital G, capital M, small m by r square.
02:32Again, the gravitational force of an object is equal to small g, capital G, capital M by capital R square.
02:41In other words, F is equal to small m into small g.
02:46Accordingly, this ball is the weight of the object.
02:50That is, the weight of the object W is equal to small m into small g.
02:56So we got the weight of the object is equal to the mass of the object into the gravitational force.
03:03The weight of the object is actually a ball.
03:06Its unit is kg into meter per second square or Newton.
03:11And its mass is the mass of the ball.
03:14That is, M L T to the power minus 2.
03:17We could understand that the weight of the object is not a fundamental religion.
03:22Its mass is dependent on the state of the object.
03:26On the other hand, gravity is a fundamental religion of the object.
03:30Its mass is unchanged with various mediums or states.
03:35Scientists have divided such a fundamental religion into two types.
03:40Inertial mass and gravitational mass.
03:46Did you get it?
03:48No, no, try to understand easily.
03:51When we studied the four religions of matter, we learned that the object does not want to change its state or position for its own weight.
04:01It has to use force from outside to change its state or position.
04:07This ball's weight is F is equal to small m into small a.
04:11For this religion, the weight is called the mass of the object or inertial mass.
04:17This object is such a religion that it is dependent on its state.
04:21Its mass can be determined by the magnitude of the object and the state of the object.
04:26That is, the mass of the object is M I is equal to F by a.
04:32Now, the gravitational ball.
04:35We have said many times that the attraction ball between two objects is called the gravitational ball of those two objects.
04:42The equation by which this ball is expressed is F is equal to gmm by r square.
04:49If one of these two objects is a supermassive object, that is, a planet, an object or a star,
04:56then the weight of that object can be determined from its attraction ball on the other object.
05:03That weight is called the gravitational weight of the object.
05:07In this case, the gravitational ball on the object is equal to that weight.
05:13That is, F is proportional to small m.
05:16Or, the gravitational weight is equal to F by gm by r square.
05:23The weight of these two objects is determined by an equation.
05:27The result of which is that the object of different weights in the world is equal in the name.
05:33From the previous two equations, we get ma is equal to gmm by r square.
05:39That is, a is equal to gm by r square.
05:42That is, the mass of the object is proportional to the gravitational weight of the object.
05:51The mass of all these objects is proportional.
05:54As a result, the mass of the object will be equal.
05:57It will not depend on the weight of the object.
06:00That is, heavy and light objects will move at the same speed.
06:05Galileo was the founder of this method.
06:08He proved the truth of this method by conducting experiments on his own subjects.
06:13The use of this method is a new discovery of modern biology.
06:18We will learn more in our next videos.
06:21Keep watching.