Presentation is loading. Please wait.

Presentation is loading. Please wait.

- Quick review and discussion of upcoming test - Visualize a scale model of the earth, sun and moon - Use the orbital motion of the moon to understand.

Similar presentations


Presentation on theme: "- Quick review and discussion of upcoming test - Visualize a scale model of the earth, sun and moon - Use the orbital motion of the moon to understand."— Presentation transcript:

1 - Quick review and discussion of upcoming test - Visualize a scale model of the earth, sun and moon - Use the orbital motion of the moon to understand its rise and set schedule TODAY’S OUTCOMES: FORCE, MOTION AND ENERGY SUN AND MOON

2 A game you can play is to give a penny a shove so that it slides across a table, trying to get it to stop on a target. You wish to find out how far the penny will go before it stops, if you give it a certain initial speed. Assume you give the penny an initial speed of 0.5 m/sec, and that the force of friction from the table is about 0.002 N. A penny has a mass of about 4 g = 0.004 kg. Kinetic energy = ½ × mass × velocity 2 = 0.5 × 0.004 kg × (0.5 m/sec) 2 = 0.002 kg × 0.25 m 2 /sec 2 = 0.0005 J C) Find the kinetic energy of the penny, and use energy conservation to find the distance the penny moves. Energy = Force × distance distance = Energy / Force = 0.0005 J / 0.002 N = 0.25 m = 25 cm

3 - Do you understand speed, velocity and acceleration? Can you interpret distance vs. time graphs? Do you understand the role of direction in velocity and acceleration? - Do you know the 3 Laws of Motion? Do you understand that forces are always balanced, but that individual objects can have unbalanced forces? Can you relate force, mass and acceleration? - Can you determine kinetic and potential energy? Can you use conservation of energy to find a distance or force? TOPICS ON THE TEST: MOTION: FORCES: ENERGY:

4 EQUATIONS: v Velocity(speed) (m/sec) d Distance (m) t Time (sec) a Acceleration (m/sec 2 ) v Change in Velocity (m/sec) t Time (sec) If initial speed is 0, then average speed = ½ × final speed If final speed is 0, then average speed = ½ × initial speed (if acceleration is constant!) a v t v d t F Force (N) m Mass (kg) a Acceleration (m/sec 2 ) D Density (g/cm 3 or kg/m 3 ) m Mass (g or kg) V Volume (cm 3 or m 3 ) m F a D m V E Energy (J) F Force (N) d Distance (m) (*force and distance must be along same direction!!!) P Power (W) E Energy (J) t Time (sec) Kinetic energy = ½ × mass × velocity 2 F E d P E t If energy is conserved, Kinetic energy + Potential energy = constant

5 - Quick review and discussion of upcoming test ✓ - Visualize a scale model of the earth, sun and moon - Use the orbital motion of the moon to understand its rise and set schedule TODAY’S OUTCOMES: FORCE, MOTION AND ENERGY SUN AND MOON

6 1. If we try to make a drawing showing sun, earth, and moon, using a scale such that the earth is a circle 1.28 cm in diameter, how large would the sun be in this drawing? Sun, Earth, Moon (Every person in the group should do this activity.) Use scaling to do this! Simple ratios: 1.28 cm x 12,800 km 1,400,000 km = earth drawing size ?(sun drawing size)? true earth size true sun size =

7 Sun, Earth, Moon (Every person in the group should do this activity.) 5. On back of this paper, make the drawing of earth and moon that you have described in Q2 and Q4. Put the “earth” near the bottom of this page, and the moon somewhere along the margin. Moon Earth Moon Nice, straight lines Measure this angle - that’s the angular size of the moon.


Download ppt "- Quick review and discussion of upcoming test - Visualize a scale model of the earth, sun and moon - Use the orbital motion of the moon to understand."

Similar presentations


Ads by Google