Conceptual Questions
Relationships
Forces and Velocity
Gravitational Force
Mixed Review
100
_________occurs when an object moves at a constant speed in a circular path.
What is uniform circular motion?
100
_____is the graphical relationship between centripetal acceleration and speed?
What is direct squared?
Formula: ac=v^2/r
100
_____is the formula to find centripetal velocity.
What is the square root of centripetal acceleration times radius?
or
What is the square root of centripetal force times radius / mass?
100
What is the formula to calculate Fg between two objects?
Fg=Gm1m2/r^2
G=6.67 times 10^-11 Nm^2/kg^2
100
Explain what acceleration for objects moving in a circular motion infers?
-Speed is constant
-Direction is constantly changing
200
_____is the time for one complete cycle.
What is period?
200
______is the relationship between centripetal force and radius.
What is inverse squared?
Formula: Fc=mv^2/r
200
A marble rolls around in an object with a radius of 30 meters. It goes around 10 times in 20 seconds.
Calculate the magnitude of the marble's instantaneous velocity.
T=10s/20
T=.5s
V=2pir/T
V=2pi(30m)/.5s
V=377 m/s
200
Calculate the gravitational force of attraction between a 10 kg bowling ball and 2 kg baseball, that are 5 m apart.
Fg=Gm1m2/r^2
Fg=(6.67 times 10^-11nm^2/kg^2)(2kg)(10kg)/(5m)^2
=5.3 times 10 ^-11 N
200
Describe any and all circumstances where the centripetal force of an object would be pointed outward?
Trick question....its centripetal force is never directed outward. It is directed toward the center of the object.
300
In which direction will the stopper travel when the string is released?
It will move tangent to the circle. 
300
______is the relationship between centripetal force and mass.
What is direct linear?
Formula: Fc=mv^2/r
300
A marble rolls around in an object with a radius of 30 meters. It goes around 10 times in 20 seconds.
Calculate the magnitude of the acceleration of the marble.
ac=v^2/r
ac=(377m/s)^2/30m
ac=4738m/s^2
300
What happens to gravitational force as the distance between centers increase?
Gravitational force decreases because of an indirect squared relationship.
300
Calculate the gravitational force of attraction between an 150kg man and the Earth.
Fg=Gm1m2/r^2
Fg=6.67 times 10^-11 Nm^2kg^2(150kg)(6 times 10 ^24 kg)/(6.37 times 10^6 m)^2
=1479 N
400
____is the type of force that occurs when an object is swung around one's head on a string.
Tension
400
_____change occurs to centripetal acceleration when mass is tripled.
What is no change?
Formulla: ac=v%\^2/r
400
A 5kg marble rolls around in an object with a radius of 30 meters. It goes around 10 times in 20 seconds.
Calculate the magnitude of the normal force acting on the marble.
Fn=Fc=mac
=5kg(4738m/s^2)
=23690 N
400
Two identical tennis balls with masses of 2kg each are 2 meters apart. Calculate the gravitational force of attraction between these two objects.
Fg=Gm1m2/r^2
Fg=(6.67 times 10^-11)(2kg)(2kg)/(2m)^2
Fg=6.67 times 10^-11 N
400
If a 10 N force exists between a 1 kg and a 2kg mass, how far are they away from each other?
Fg=Gm1m2/r^2
r=square root(Gm1m2/Fg)
r=square root(6.67 times 10^-11Nm^2/kg^2(1kg)(2kg)/10 N
r=1.2 times 10^-6 m
500
Newton's law_______states that all objects are attracted to all other objects due to their_______.
What is Newton's Law of Universal Gravitation?
What is mass?
500
Given ac = 30 m/s^2
What happens to ac when the radius is doubled? Show work.
ac= v^2/r
ac=(1)^2/2
ac=1/2
1/2 times 30 m/s^2
ac= 15 m/s^1
500
A 100 kg person flies a 10 kg motorized plane on a 5 m string in a circular path. The plane has a T of 2s.
What is the speed of the plane?
V=2pir/T
V=2pi(5m)/2s
V=16m/s
500
What is the gravitational force between the earth and the moon? How fast is the moon traveling around the Earth?
Fg=Fc=mv^2/r
v=square root ((Fc)(r))/m
v=square root (2 times 10^20N)(3.84 times 10^8 m)/7.35 times 10^22 kg
=1022 m/s
500
A 5kg rubber stopper completes 20 cycles in 40 seconds on a 5 meter long string.
What is the period and speed?
T=40s/20
T=2s
V=2pir/T
V=2pi(5m)/2s
V= 16 m/s