Gravitation Jeopardy Universal Law of Gravitation Kepler’s Laws AstronomyCircular Motion

Part 1: Universal Law of Gravitation

10 Points – ULG Using Newton’s Universal Law of Gravitation, if the mass of one of the objects increases by 5, what happens to the force exerted between them? AnswerMain

10 Points Answer – ULG The force increases by 5. MainQuestion

20 Points - ULG Using Newton’s Universal Law of Gravitation, if the radius between the objects increases by 5, what happens to the force exerted between them? MainAnswer

20 Points Answer – ULG The force decreases by 5 2 Or the force is 1/25 of the original force. MainQuestion

30 Points - ULG MainAnswer Using Newton’s Universal Law of Gravitation, if the radius between the objects decreases by 5, what happens to the force exerted between them?

30 Points Answer – ULG The force increases by 5 2 Or the force is 25 times the original force. MainQuestion

40 Points – ULG MainAnswer Determine the gravitational force exerted by cookie monster on a nearby cookie. – Mass of cookie monster: 200 kg – Mass of cookie: 0.3 kg – Distance between them: 5 m – G: 6.67 x

40 Points Answer – ULG F = Gm 1 m 2 /r 2 = (6.67x )(200kg)(0.3kg)/(5m 2 ) = 1.6 x N MainQuestion

50 Points – ULG MainAnswer Graph gravitational force versus the distance between two objects How are these two physical quantities related? – Directly proportional – Directly proportional to the square of the distance – Inversely proportional – Inversely proportional to the square of the distance

50 Points Answer – ULG How are these two physical quantities related? -Directly proportional -Directly proportional to the square of the distance -Inversely proportional -Inversely proportional to the square of the distance MainQuestion

60 Points – ULG MainAnswer State Newton’s Law of Universal Gravitation.

60 Points Answer – ULG F grav = Gm 1 m 2 /r 2 Gravitational force = Gravitational constant*mass1*mass2/radius 2 MainQuestion

Part 2: Kepler’s Laws Main

10 Points – Kepler MainAnswer What is Kepler’s First Law? What is at one focus?

10 Points Answer – Kepler Kepler’s First Law: All planets orbit around the sun in an elliptical shape. The sun is at one focus. MainQuestion

20 Points – Kepler What is Kepler’s Second Law? What does it tell you about the speed of an object in an elliptical orbit? MainAnswer

20 Points Answer – Kepler Objects sweep out equal areas in equal amounts of time in their orbit T1 = T2 if A1 = A2 Objects travel faster when closer to the sun MainQuestion

30 Points – Kepler State Kepler’s Third Law. What ratio is equal to Kepler’s constant for all bodies orbiting the sun? MainAnswer

30 Points Answer – Kepler The period squared divided by the semi-major axis cubed is equal to Kepler’s constant. Kepler’s constant is equal to 1. MainQuestion

40 Points – Kepler DOUBLE JEOPARDY!!! What does stellar retrograde motion depict? Why does Kepler’s First Law explain this phenomena? MainAnswer

40 Points Answer – Kepler Stellar retrograde motion is when stars or planets appear to move backwards in the sky. We orbit the sun instead of all planets orbiting us; therefore, if we pass another planet as we circle the sun – it appears as though that planet is travelling backwards. MainQuestion

50 Points – Kepler Earth moves more slowly in its orbit during June than during January. Is Earth closer to the sun in June or in January? What is the rationale for your answer? MainAnswer

50 Points Answer – Kepler MainQuestion Earth is closer to the sun in January. Since it travels slower in June, that means the gravitational pull is less which means Earth must be farther away in June.

60 Points – Kepler Sketch the force and velocity arrows at each point in this diagram. MainAnswer

60 Points Answer – Kepler MainQuestion Velocity arrows are red – always tangent to the ellipse Force arrows are green – always pointed toward the focus

Part 3: Astronomy Main

10 Points – Astronomy What are the two types of planets and what are their main differences? MainAnswer

10 Points Answer – Astronomy Terrestrial and Jovian – Terrestrial are rocky planets – Jovian are the gas giants MainQuestion

20 Points – Astronomy What are the criteria for being a planet? MainAnswer

20 Points Answer – Astronomy MainQuestion Need to clear out the space in their orbit Need to be circular in shape Need to orbit the sun

30 Points – Astronomy MainAnswer How does the gravitational force exerted by one planet in space on a second relate to the force exerted by the second planet on the first?

30 Points Answer – Astronomy The forces are equal (Newton’s Third Law) and opposite in direction. MainQuestion

40 Points – Astronomy MainAnswer List the planets around our sun in order.

40 Points Answer – Astronomy Mercury, Venus, Earth, Mars Jupiter, Saturn, Uranus, Neptune MainQuestion

50 Points – Astronomy Explain what causes tides. AnswerMain

50 Points Answer – Astronomy The moon pulls on each side of the Earth differently, causing high tides on the side closest to the moon and further away. QuestionMain

60 Points – Astronomy What are comets? What shape do their orbits make? How does that help explain why comets may not have originally been part of the solar system? AnswerMain

60 Points Answer – Astronomy Comets are balls of dust and ice. They orbit in very eccentric orbits (very oval shapes) so they are not seen for very long periods of time Because comets appear so irregularly, astronomers were not able to chart their course as easily as the other planets. QuestionMain

Part 1: Circular Motion

10 Points – CM What direction is the acceleration for an object spinning in a circle? AnswerMain

10 Points Answer – CM Towards the center of the circle MainQuestion

20 Points - CM Anna Litical is practicing a centripetal force demonstration at home. She fills a bucket with water, ties it to a strong rope, and spins it in a circle. Why does the water not fall out? MainAnswer

20 Points Answer – CM Inertia keeps the water moving in a straight line, so the water “pushes against the back of the bucket” keeping it from falling out. MainQuestion

30 Points - CM MainAnswer A 900-kg car moving at 10 m/s takes a turn around a circle with a radius of 25.0 m. Determine the acceleration and the net force acting upon the car.

30 Points Answer – CM TOK: -m = 900kg -v = 10 m/s -r = 25.0 m a = v 2 /r = 10 2 /25 = 4 m/s 2 F = ma = 900*4 = 3600 N MainQuestion

40 Points – CM MainAnswer A tube is been placed upon the table and shaped into a three-quarters circle. A golf ball is pushed into the tube at one end at high speed. The ball rolls through the tube and exits at the opposite end. Describe the path of the golf ball as it exits the tube.

40 Points Answer – ULG MainQuestion Will leave the tube in the direction it was moving already (inertia)

50 Points – CM MainAnswer You want to make a bowling ball travel in a circular counter-clockwise path around you (this means YOU are the center point). After you set the ball in motion “to the left”, in what direction will force need to be exerted to keep the ball in a circular path? – You need to constantly push the ball away from you – You need to constantly push the ball toward you. – You need to constantly push the ball to the left

50 Points Answer – CM You want to make a bowling ball travel in a circular counter-clockwise path around you (this means YOU are the center point). After you set the ball in motion “to the left”, in what direction will force need to be exerted to keep the ball in a circular path? – You need to constantly push the ball away from you – You need to constantly push the ball toward you. – You need to constantly push the ball to the left MainQuestion

60 Points – CM MainAnswer Determine the centripetal force acting upon a 40-kg child who makes 10 revolutions around the Cliffhanger in 29.3 seconds. The radius of the barrel is 2.90 meters.

60 Points Answer – CM T = sec/rev = 29.3s/10rev = 2.93s v = 2πr/T = 2π(2.90m)/2.93s = 6.2m/s F = mv 2 /r = (40kg)(6.2 2 m/s)/(2.90m) = N MainQuestion

Physics CP Jeopardy Gravitation, Kepler’s Laws and Astronomy Review Main