So what's 0.981 times 10? Well, the force is equal to 9.81 0.981, and then 10 to the 13thĭivided by 10 to the 12th is just 10, right? 10 to the first, times 10, That's just this dividedīy 10 to the 12th. Is equal to the mass of Sal times- let's divide, 39.82ĭivided by 40.58 is equal to 9.81. This little calculator I haveĭoesn't have squared, so I have to- so it's 40.58. This is is going to be like 37 or something- times- what'sġ0 to the sixth squared? It's 10 to the 12th, right? 10 to the 12th. So what's 24 minus 11? It's 10 to the 13th, right? And then what does theĭenominator look like? It's going to be the 6.37 So 10 to the negative 11th timesġ0 to the negative 24th. This, so now I have to multiply the 10's. Force is equal to- let's bring theĭo this top part. Notation since everything else is in scientific notation-Ħ.371 times 10 to the sixth meters, right? 6,000 kilometers isĦ million meters. Meter to get to my center of mass, we can ignore for now,īecause it would be. How many meters is that? It's 6 million meters, right? And then, you know, the extra I also looked it up on Wikipedia- 6,371 kilometers. Anyway, my center of mass mightīe three feet above the ground, and where's Earth'sĬenter of mass? Well, it's at the center ofĮarth, so we have to know the radius of Earth, right? So the radius of Earth is. For all general purposes, myĬenter of mass, maybe it's like three feet above The distance between their center of masses. We're talking about the universal law of gravitation, is That the distance between the two objects, especially when The distance between someone standing on theĮarth and the Earth? Well, it's zero because they're Weighs a little bit, not weighs, is a littleīit more massive than Sal- divided by the distance Mass of Earth, times 5.97 times 10 to the 24th kilograms. And then what's the mass 2? It's the mass of Earth. My mass in this video, so I'll just leave 6.67 times 10 to the negativeġ1th, and we want to know the acceleration on Sal, so To have to work with meters in kilograms seconds. That when you multiply it times a mass and a massĭivided by a distance squared, you get Newtons, or kilogram I know these units are crazy,īut all you have to realize is these are just the units needed, But for our purposes, it is aĬonstant, and the constant in most physics classes, is this:Ħ.67 times 10 to the negative 11th meters cubed per kilogram I'm not an expert on this, I actually think its measurementĬonstant, or I guess when on different scales, it can beĪ little bit different. What's this big G thing? The G is the universal Towards the center of Earth or the Earth's center of mass? The force is equal to- so And so how do we apply thisĮquation to figure out how much I'm accelerating down Out the gravitational acceleration on Sal. Just so we know what we're talking about. To figure out what the acceleration, the gravitationalĪcceleration, is at the surface of the Earth. So let's play around with this,Īnd see if we can get some results that look

Second object divided by the distance between the two Times the mass of the first object times the mass of the Gravitational force, is equal to the gravitational constant G That the force between two masses, and that's the Newton's Law of Gravity, and this works for most purposes. It's really, at least to me,Ī little bit mystical. Objects, just because they have this thing called Kind of say, oh, well, it's the warping of space time andĪll of this, but it's hard to get an intuition of why two Relativity, if you do get there, I have to say, you can Important variables in it, but it's something that's really Something that, especially in introductory physics orĮven reasonably advanced physics, we can learn how toĬalculate it, we can learn how to realize what are the If you want to know how G came about, read on the 'Cavendish experiment' Everest your radius will be larger than if you were in Death Valley. That is why g can change from place to place on earth. If you are twice as far out 2*r, you will have 4 times less gravitational acceleration. Notice if you change your radius that the acceleration(g) will fall off as 1/r^2. If you put in the mass of the earth and the radius to sea level you will get 9.8 m/s^2 for a. Notice that little m cancels out on both sides of the equation. Here you use the radius of the earth for r, the distance to sea level from the center of the earth, and M is the mass of the earth. You get this value from the Law of Universal Gravitation. The 9.8 m/s^2 is the acceleration of an object due to gravity at sea level on earth. G is the local acceleration due to gravity between 2 objects.

G is the universal constant for the gravitational force.

Physics phenomena gravity