PHY-Unit 2.3 (Circular+Gravitation)

Which system has the greater gravitational attraction between the two objects (if any)?

• System A
• System B
• Same gravitational attraction fro System A and System B

If I double the distance between two objects, what happens to their gravitational Force?

• 4x bigger
• 4x smaller
• 2x bigger
• 2x smaller

What two things determine the gravity of an object?

• mass & weight

• mass & distance

• density & mass

• volume & distance

When will the forces of gravity between two objects be the GREATEST?

• when the masses of both objects are small and the objects are far apart

• when the masses of both objects are large and the objects are close together

• when the masses of both objects are small and the objects are close together

• when the masses of both objects are large and the objects are far apart

The sun has more mass than Earth. Why doesn't the moon orbit the sun instead of Earth?

• The moon is closer to Earth than the sun so its gravitational pull is more.
• It does orbit the sun because of Earth's orbit around the sun.
• The Earth has a greater mass than the sun.
• Earth's magnetic field is so strong it pulls the moon close.

Which of the following best describes the formation of the solar system?

• The Sun ejected rocky material which formed the planets due to magnetic attraction forces.

• A rotating disk of gas and dust was drawn together by the force of gravity.

• One very large planetary body broke apart into several smaller planets.

• Several stars of different masses cooled and formed the planets and the Sun.

Which of the following describes the relationship between planets and their orbital speed?

• Planets closest to the Sun will orbit with the fastest orbital speed.

• Planets with the greatest mass will orbit the Sun with the fastest orbital speed.

• Planets furthest from the Sun will orbit with the fastest orbital speed.

• Planets with the least mass will orbit the Sun with the fastest orbital speed.

A horse gallops around a circular arena.  The centripetal force on the horse is ___.

• directed outward
• tension
• directed toward the center of the arena
• 9.8 N

Calculate the amount of centripetal force it takes for a softball pitcher to rotate a ball with a velocity of 3 m/s if the ball weighs .12 kg and her arm is .65 meters long.

• .38
• 1.23
• .55
• 1.66 N

An engineer is planning a road with a turn. If the speed limit is 20 m/s and the centripetal acceleration cannot exceed 8.5 m/s/s, how big must the radius of the turn be?

• 2.4 m

• 47 m

• 170 m

• 3400 m