Circular Motion, Gravitation, Kepler’s 3d Law, Orbits Variables, Equations, and Constants
Variables
Variables (units) a c (m/s 2 ) centripetal acceleration
Variables (Units) T (s) Period time of one complete rotation or revolution
Variables (units) r (m) Radius of Orbit
Variables (units) v (m/s) speed of orbit orbital velocity
Variables (units) F G (N) Force of gravitational attraction
Equations
Centripetal Accleration
Centripetal Acceleration
Kepler’s 3d law
Universal Law of Gravitation
Period of Orbiting Body
Speed of an Orbiting Body
Constants
Definition of the Astronomical Units (AU)
Universal Gravitational Constant
Chapter 9 Impulse and Momentum
Definitions impulse (J)—a force exerted over an interval of time. Impulse is measured in Ns.
Definitions momentum (p)—the product of mass and velocity. Momentum is measured in kgm/s.
Relationship between impulse (J) and momentum (p) Slide 1 of 3 Equation/OperationMeaning Newton’s second law of motion Definition of acceleration Multiplication Definition of Δv Distributive Property
Relationship between impusle (J) and momentum (p) Slide 2 of 3 Equation/OperationMeaning Definition of Momentum Definition of delta Definition of impulse Relationship between impulse and momentum
Relationship between impulse (J) and momentum (p) Slide 3 of 3 This equation says that an impulse causes a change in momentum. Or in other words, a push acting for a certain time changes an object’s motion.
Examples
Show that a Ns is the same as a kgm/s.
Examples 1.Calculate the momentum of 0.50 kg ball rolling at 12 m/s. 2.Calculate the momentum of a 1300 kg car travelling at 72 km/h. 3.Calculate the momentum of a 45 g bullet travelling at 400 m/s. 4.The momentum of a person walking at 0.8 m/s is 96 kgm/s. a.What is the person’s mass? b.What is the person’s weight in N c.What is the person’s weight in lbs?
Examples 1.Calculate the momentum of 0.50 kg ball rolling at 12 m/s. P = mv P = 6 kgm/s
Examples 2.Calculate the momentum of a 1300 kg car travelling at 72 km/h. P = mv P = 2.6 E4 kgm/s
Examples 3.Calculate the momentum of a 45 g bullet travelling at 400 m/s. P = mv P = 18 kgm/s
Examples 4.The momentum of a person walking at 0.8 m/s is 72 kgm/s. a.What is the person’s mass? b.What is the person’s weight in N? c.What is the person’s weight in lbs? p = mv m=p/v m=90 kg W = 882 N W= 200 lbs.