Define it!
True or False?
Forces
Gravity
Circular Motion
Grab Bag
100

This is a mythical force. The supposed effect of this “force” is just Newton’s First Law.

Centrifugal Force
#11 SG

100

Earth, Saturn, Uranus, Jupiter, and Neptune all have rings.

False
(All of these have rings except Earth.)
#15 SG

100

Name the four fundamental forces in creation.

The gravitational force, the weak force, the strong force, & the electromagnetic force (all forces in creation can be traced back to one of these)
#1a SG

100

According to Einstein’s Theory of General Relativity, this causes gravity.

The fact that objects with mass bend space and time
#22 SG

100

Name one principle of circular motion (or name all 3 and get 500 points total – add 400 to your total online).

1. Circular motion requires centripetal force.
2. The larger the centripetal force, the faster an object travels in a circle of a given size.
3. At a given speed, the larger the centripetal force, the smaller the circle.
#9 SG (1st chance)

100

Most physicists think short-period comets come from this belt in space.

The Kuiper belt
#21 SG

200

The planets Mercury, Venus, Earth, and Mars are considered to be the ____ planets. (Inner or Outer)

Inner planets
#13a SG

200

Comets’ orbits are elliptical.

True
(not circular)
#20 SG

200

This is the strongest fundamental force.

Strong force
(responsible for holding the center of the atom – the nucleus – together; its range is very small)
#2a SG

200

According to the graviton theory, this causes gravity.

The exchange of particles called “gravitons”
#23 SG

200

When a ball follows a circle going clockwise, this is the direction of the velocity it experiences if it is traveling at constant speed.

Straight
(since it is traveling at constant speed, the only force is centripetal, which always points to the center of the circle)
#12a SG

200

This causes an asteroid to become a meteor.

Perturbations in the asteroid’s orbit
#17 SG

300

The planets Jupiter, Saturn, Uranus, and Neptune are considered to be the ____ planets. (Inner or Outer)

Outer
#13b SG

300

Most of the asteroids in the solar system are between the orbits of Mars and Earth.

False
(most asteroids are between the orbits of Mars and Jupiter – in the asteroid belt)
#16 SG

300

This is the weakest fundamental force.

The gravitational force
(always an attractive force; any two objects that have mass are attracted to one another by the gravitational force that exists between them)
#2b SG

300

The gravitational force between 2 objects (mass 1 = 10 kg, mass 2 = 6 kg) is measured when the objects are 10 cm apart. If each mass is changed to double what it was, how does the new gravitational force compare to the first one measured?

The new gravitational force is 4 times larger than the first one measured
(doubling the mass for each object doubles the gravitational force of each, so 2 x 2 = 4 times larger)
#4 SG

300

When a ball follows a circle going clockwise, this is the force it experiences if it is traveling at constant speed.

Centripetal
(and it always points to the center of the circle)
#12b SG

300

This part of a comet is always present.

The comet’s nucleus
#18b SG

400

This projectile in space can have three parts, depending on where it is in its orbit.

A comet is made of a nucleus, a coma, and a tail. The nucleus is always present.
#18a SG

400

The planets of the solar system in order, starting closest to the sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

True
#14 SG

400

This is the kind of force necessary for circular motion.

Centripetal force
(The force necessary to make an object move in a circle. It is directed perpendicular to the velocity of the object, which means it points toward the center of the circle.)
#8 SG

400

The gravitational force between 2 objects (mass 1 = 10 kg, mass 2 = 6 kg) is measured when the objects are 10 cm apart. If the distance between them is increased to 40 cm, how does the new gravitational force compare to the first one measured?

The new gravitational force is 16 x smaller than the first one (the distance between the objects was multiplied by 4; gravitational force decreases when distance between objects increases, and it decreases according to the square of that increase. Thus, the force is divided by 42, which is 16.)
#5 SG

400

To do a “hammer throw,” an athlete twirls a massive ball at the end of a wire. He releases the wire at top speed, allowing the ball to fly straight out onto the field. The longest flight wins.
As the ball twirls faster, the wire will need to apply more, less, or the same amount of centripetal force.

The wire will need to exert more force
(because objects that travel fast need large centripetal force)
#10a SG

400

During this part of a comet’s orbit, all three parts are present (its nucleus, coma, and tail).

When the comet is close to the sun
#19 SG

500

Name all 3 principles of circular motion (or name just 1 and get 100 points – subtract 400 from your total online). 

1. Circular motion requires centripetal force.
2. The larger the centripetal force, the faster an object travels in a circle of a given size.
3. At a given speed, the larger the centripetal force, the smaller the circle.
#9 SG (2nd chance)

500

The three principles of Newton’s Universal Law of Gravitation are:
1. All objects with mass are attracted to one another by the gravitational force.
2. The gravitational force between two masses is directly proportional to the mass of each object.
3. The gravitational force between two masses is inversely proportional to the square of the distance between those two objects.

True
#3 SG

500

Name the two fundamental forces in creation that are really different aspects of the same force.

Electromagnetic force (between particles with electrical charge) & weak force (governs certain radioactive processes in atoms)
(Note: Scientists have combined & renamed the two forces the “electroweak force”)
#1b SG

500

The gravitational force between 2 objects (mass 1 = 1 kg, mass 2 = 2 kg) is measured when the objects are 12 cm apart. If the masses are increased (mass 1 = 5 kg, mass 2 = 4 kg), and the distance between the objects is reduced to 4 cm, how does the new gravitational force compare to the first one measured?

The new gravitational force is 90 x larger
(Mass 1 x 5 = gravitational force x 5. Mass 2 x 2 = gravitational force x 2. The distance between the objects was divided by 3 = gravitational force x 32 = 9. The total change is 5 x 2 x 9 = 90.)
#6 SG

500

To do a “hammer throw,” an athlete twirls a massive ball at the end of a wire. He releases the wire at top speed, allowing the ball to fly straight out onto the field. The longest flight wins.
He grips the wire close to the ball, making small circles. Then, keeping the speed of the ball constant, he lets some wire slip through his hands to make larger circles. The wire will then exert more, less, or the same amount of centripetal force after he makes the adjustment.

The wire will exert less force
(because the larger the centripetal force, the smaller the circle; so a larger circle needs less centripetal force to go the same speed)
#10b SG

500

If Venus orbits the sun because the sun exerts a gravitational force on it, this is the equal and opposite force required by Newton’s Third Law of Motion.

The gravitational force that Venus exerts on the sun
#7 SG

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