All AP Physics 1 Resources
Example Questions
Example Question #41 : Universal Gravitation
Pluto radius:
Pluto mass:
Determine the gravity constant, on the surface of Pluto.
Set both forms of gravitational force equal to each other.
Simplify:
Plug in values:
Example Question #81 : Forces
How would the linear velocity of the Moon be different if it's mass was doubled? Assume that the distance to the Earth stayed the same.
Unchanged
Quadrupled
Quartered
Doubled
Halved
Unchanged
Set centripetal force equal to gravitational force:
The mass of the Moon, cancels out, thus, there is no effect.
Example Question #43 : Universal Gravitation
If on earth you have a weight, , what would your new weight be if you were standing on a planet with the same mass as earth, but with half the radius?
your earth weight.
The same as your earth weight.
times your earth weight
your earth weight.
times your earth weight.
times your earth weight.
Your weight is a function of how much force is pulling you down towards the planet, not just your mass. To find force when your standing on a different planet, you would need to use Newton's Law of Universal Gravitation.
To compare the forces from each planet, you would set this equation equal to itself.
We then cancel the common terms, in this formula that's the negative sign, (the gravitational constant), and the mass of the earth/planet (because they're the same). After that we can substitute the radius of the new planet for half of the earth radius.
We need to remember that when we square the radius in the Law of Universal Gravitation, we also need to square the , making it . Because the is in the denominator, we take the inverse of it, so you would feel times more force standing on the new planet. Therefore you would have times as much weight.
Example Question #82 : Forces
An electronic scale is used to find the mass of a lead cube at sea level. The scale and lead cube are then transported to the top of a mountain, over above sea level. How does the weight reading compare to the weight given at sea level?
None of these
It is impossible to determine
It will be larger
It will be the same
It will be smaller
It will be smaller
The electronic scale measures based on the normal force the scale provides to the object. This in turn is based on the force of gravity on the object by the earth.
As height above sea level increases, as does , the distance to the center of the Earth. As increases, decreases. This would decrease the normal force which would decrease the reading on the scale.
Example Question #83 : Specific Forces
Mass of moon:
Radius of moon:
A spring of rest length is placed upright on the moon. A mass of is gently placed on top and the spring contracts by . Determine the spring constant.
None of these
First, estimate the acceleration due to gravity close to the moon's surface:
Combining equations and solving for the acceleration:
Converting to and pugging in values:
Using
Solving for
Converting to and plugging in values:
(Since the mass is at rest, the acceleration and thus the net force is zero)
Example Question #53 : Universal Gravitation
A rope is used to accelerate a mass upwards at . Determine the tension in the rope.
None of these
Using
Combining equations:
Solving for and plugging in values:
Example Question #52 : Universal Gravitation
Mass of Earth:
Universal gravitation constant:
Radius of earth:
Determine the magnitude of gravitational force by the earth on a astronaut above the surface of the earth.
Finding total distance from center of Earth to astronaut:
Converting to meters
Using Universal Gravitation equation:
Plugging in values:
Example Question #53 : Universal Gravitation
Mass of Jupiter:
Universal gravitation constant:
Radius of Jupiter:
A marble is placed from the surface of Jupiter. Determine the acceleration due to the gravity of Jupiter.
None of these
Using
and
Combining equations
Solving for
Plugging in values:
Example Question #52 : Universal Gravitation
Mass of Pluto:
Radius of Pluto:
A spring of rest length is placed upright on Pluto. A mass of is gently placed on top and the spring contracts by . Determine the spring constant.
None of these
First, estimate the acceleration due to gravity close to Pluto's surface:
Combining equations and solving for the acceleration:
Plugging in values:
Using
Solving for
Converting to and plugging in values:
(Since the mass is at rest, the acceleration and thus the net force is zero)
Example Question #54 : Universal Gravitation
Mass of Mars:
Radius of Mars:
A spring of rest length is placed upright on Mars. A mass of is gently placed on top and the spring contracts by . Determine the spring constant.
None of these
First, estimate the acceleration due to gravity close to the martian surface:
Combining equations and solving for the acceleration:
Plugging in values:
Using
Solving for
Converting to and plugging in values:
(Since the mass is at rest, the acceleration and thus the net force is zero)
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