14
Monday Gravitational force.notebook 1 December 04, 2016 Return to Table of Contents Gravitational Force https://www.njctl.org/video/?v=IP_u0xQvP04
Monday Gravitational force.notebook
1
December 04, 2016
Return toTable ofContents
Gravitational Force
https://www.njctl.org/video/?v=IP_u0xQvP04
Monday Gravitational force.notebook
2
December 04, 2016
Newton’s Law of Universal Gravitation
It has been well known since ancient times that Earth is a sphere and objects that are near the surface tend fall down.
Monday Gravitational force.notebook
3
December 04, 2016
Newton’s Law of Universal GravitationNewton connected the idea that objects, like apples, fall towards the center of Earth with the idea that the moon orbits around Earth...it's also falling towards the center of Earth.
The moon just stays in circular motion since it has a velocity perpendicular to its acceleration.
https://www.njctl.org/video/?v=uhS8K4gFu4s
Monday Gravitational force.notebook
4
December 04, 2016
Newton’s Law of Universal Gravitation
Newton concluded that all objects attract one another with a "gravitational force". The magnitude of the gravitational force decreases as the centers of the masses increases in distance.
M1 M2
r
M1 M2
r
MORE Gravitational attraction
LESS Gravitational attraction
Monday Gravitational force.notebook
5
December 04, 2016
G = 6.67 x 1011 Nm2 /kg2
Gravitational Constant
In 1798, Henry Cavendish measured G using a torsion beam balance. He did not initially set out to measure G, he was instead trying to measure the density of the Earth.
https://www.njctl.org/video/?v=2PdiUoKa9Nw
Monday Gravitational force.notebook
6
December 04, 2016
Newton’s Law of Universal GravitationMathematically, the magnitude of the gravitational force decreases with the inverse of the square of the distance
between the centers of the masses and in proportion to the product of the masses.
Monday Gravitational force.notebook
7
December 04, 2016
Newton’s Law of Universal Gravitation
The direction of the force is along the line connecting the centers of the two masses. Each mass feels a force of attraction towards the other mass...along that line.
r
Monday Gravitational force.notebook
8
December 04, 2016
Newton’s Law of Universal Gravitation
Newton's third law tells us that the force on each mass is equal.
That means that if I drop a pen, the force of Earth pulling the pen down is equal to the force of the pen pulling Earth up.
However, since the mass of Earth is so much larger, that force causes the pen to accelerate down, while the movement of Earth up is completely unmeasurable.
Monday Gravitational force.notebook
9
December 04, 2016
1 What is the magnitude of the gravitational force between two 1 kg objects which are located 1.0 m apart?
A 3.3 x 1011 NB 1.7 x 1011 N C 2.7 x 1010 N D 6.7 x 1011 N
Answer
https://www.njctl.org/video/?v=IP_u0xQvP04
Monday Gravitational force.notebook
10
December 04, 2016
2 What is the magnitude of the gravitational force acting on a 4.0 kg object which is 1.0 m from a 1.0 kg object?
A 3.3 x 1011 NB 1.7 x 1011 N C 2.7 x 1010 N D 6.7 x 1011 N
Answer
https://www.njctl.org/video/?v=dPFsPm5UYhg
Monday Gravitational force.notebook
11
December 04, 2016
3 What is the magnitude of the gravitational force acting on a 1.0 kg object which is 1.0 m from a 4.0 kg object?
A 3.3 x 1011 NB 1.7 x 1011 N C 2.7 x 1010 N D 6.7 x 1011 N
Answer
https://www.njctl.org/video/?v=iOovJt1I8lc
Monday Gravitational force.notebook
12
December 04, 2016
4 What is the magnitude of the gravitational force acting on a 1.0 kg object which is 2.0 m from a 4.0 kg object?
A 3.3 x 1011 NB 1.7 x 1011 N C 2.7 x 1010 N D 6.7 x 1011 N
Answer
https://www.njctl.org/video/?v=tjkf5sqwLT0
Monday Gravitational force.notebook
13
December 04, 2016
5 What is the magnitude of the gravitational force between Earth and its moon? r = 3.8 x 108m mEarth = 6.0 x 1024kg mmoon = 7.3 x 1022 kg
A 2.0 x 10 18 NB 2.0 x 1019 NC 2.0 x 1020 ND 2.0 x 1021 N
Answer
https://www.njctl.org/video/?v=4MieN1BT4Yc
Monday Gravitational force.notebook
14
December 04, 2016
https://www.njctl.org/video/?v=mAC5GoXjJGE
6 What is the magnitude of the gravitational force between Earth and its sun? r = 1.5 x 1011 m mEarth = 6.0 x 1024kg msun = 2.0 x 1030 kg
A 3.6 x 1018 NB 3.6 x 1019 N C 3.6 x 1021 N D 3.6 x 1022 N A
nswer
