PHYSICS 103 Lecture 11 Agenda for Today Circular
- Slides: 12
PHYSICS 103: Lecture 11 Agenda for Today: • Circular Motion (continued) • Gravity and orbital motion • Example Problems
HW (due Tuesday) Read Chapter 6
CENTRIPETAL FORCE: EXAMPLE • ROTATING SPACE SHIP: MOVIE 2001
FORCE OF GRAVITY • Attractive force between all massive objects • Increases with increasing masses • Increases as the two objects get closer by r-2 G = 6. 67 10 -11 N m 2/kg 2
Gravitational Force Between People • Calculate the gravitational force between you and your neighbor. Assume your masses are 100 kg and the distance between you is 50 cm. Compare this to the gravitational force between you and the Earth. The radius of the Earth is 6370 km and its mass is 5. 98 1024 kg.
ORBITAL SPEEDS
Example: What is the speed of the Moon? 1) Newton’s Law of Motion 2) Newton’s Law of Gravitation 3) Circular motion F = m a F = (G m M) / r 2 a = v 2 / r
Steps. . . acceleration of mass is a = v 2/r therefore force acting on object is f = m a = m v 2/r If object (m) is circling another massive object (M), then f = G m M/r 2 i. e. , m v 2/r = G m M/r 2 v 2 = G M/r
Orbital velocity How fast does the moon orbit? v » 1000 m/s How fast does a satellite orbit? v » 7800 m/s (17, 400 miles/hr!)
Problem: Speed of moon? r Data: r = 3. 84 108 m G = 6. 67 10 -11 N Me = 5. 98 1024 kg V = 1020 m/s
Problem: Speed of moon? Data: r = 3. 84 108 m Steps: speed = distance / time period total dist. = 2 p r = 2 p 3. 84 108 (m) time period = 27. 3 24 60 (s) speed = (2. 4 109) / (2. 4 106) = ~ 1 103 m/s
Main Points from Today’s Lecture • Gravity You should understand that gravity is a force that exists between all objects and that it is proportional to the masses of the objects and inversely proportional to the distance squared. • Gravity and Orbital Motion You should understand that gravity is a force that exists between all objects. It is the force that is responsible for the moon orbiting the earth, the earth orbiting the sun, etc. The orbital velocity of anything is where M is the mass of the central body being orbited.
- 01:640:244 lecture notes - lecture 15: plat, idah, farad
- Agenda sistemica y agenda institucional
- Agenda for today
- Today meeting or today's meeting
- Are we having class today
- Proposal kickoff meeting agenda
- Today lesson or today's lesson
- Today's lesson or today lesson
- Example of repitition
- Directional lines in hair
- Physics 111 lecture notes
- Physics 101 lecture notes pdf
- Physics 101 lecture 1