AP Quiz Gravitational force and gravitational field

A satellite of mass m orbits a moon of mass M in uniform circular motion with a constant tangential speed of v.

The gravitational field strength at a distance R from the center of moon is g. The satellite is moved to a new circular orbit that is 2R

from the center of the moon. What is the gravitational field strength of the moon at this new distance?

• g/4

• g/2

• 2g

• 4g

A 2 kg object is a distance of 10,000,000 m away from the center of Earth, which has a mass of nearly 6×10^24 kg. What is the approximate gravitational field strength of Earth’s gravitational field at the location of the 10 kg object?

• 2 N/kg

• 4 N/kg

• 10 N/kg

• The gravitational field strength is negligible and, therefore approximately zero.

A space station has a mass M and orbits Earth in a circular orbit at a height above Earth’s surface.

A payload of mass m, where m<M, is delivered to the space station. Soon after, the space station’s orbit is adjusted so that it is 50 km farther away from Earth’s surface than before. Which of the following best describes the effects of these changes on Earth’s gravitational field strength at the space station’s new location?

• The increase in mass of the space station has no effect on the field strength, and the increase in orbital radius decreases the field strength.

• The increase in mass increases the field strength, and the increase in orbital radius decreases the field strength; however, the field strength decreases overall.

• The increase in mass increases the field strength, and the increase in orbital radius decreases the field strength; however, the field strength increases overall.

• The field strength is unchanged because there is no gravitational field in space.

A satellite of mass 1000 kg is in a circular orbit around a planet. The centripetal acceleration of the satellite in its orbit is 5 m/s^2. What is the gravitational force exerted on the satellite by the planet?

• 0

• 200 N

• 5,000 N

• 10,000 N

A car rounds a curve at constant speed. If the car's speed doubles, the net force on the car is multiplied by a factor of

• one fourth

• one half

• the net force does not change

• two

• four

A 3.0 kg block starts from rest at the top of a 30⁰ incline and slides 2.0 m, measured along the incline, in 1.5 s. Is normal force on the block

• Greater than 30 N

• Less than 30 N

• Equal to 30 N

What is the direction of the centripetal acceleration for a mass whirled on a string in a vertical circle, when the mass is a the top of the circle?

• Up

• Down

• Left

• Right

• In the direction that the mass is moving

What is the direction of the centripetal acceleration for a mass whirled on a string in a vertical circle, when the mass is a the bottom of the circle?

• Up

• Down

• Left

• Right

• In the direction that the mass is moving

A mass is whirled on a string in a vertical circle, Where is the tension in the string largest?

• At the top of the circle

• At the bottom of the circle

• Nowhere, the tension is the same everywhere

• Neither at the top, nor at the bottom, but somewhere in between

An astronaut lands on a planet whose mass and radius are each twice that of earth. If the astronaut weighs 800 N on earth, how much will he weigh on this planet?

• 200 N

• 400 N

• 800 N

• 1600 N

• 3200 N