Circles, Circles, Circles
What is the distance covered by an object going in a circle one time? How can we calculate this?
The circumference of the circle. 2*pi*r.
True/False. Gravity is affected by the mass of only the largest object.
False
Why do the objects in this room not accelerate towards me because of Gravity?
The force of gravity is very small in this case, and friction keeps this from happening
If I spin a stopper above my head with a radius of 1m, and it takes 1.5 seconds to go in one complete circle. What is the velocity of the stopper?
1.33(pi) m/s OR 4.19 m/s
The moon has an acceleration due to gravity of 1.6m/s2. How much would a 100kg dog weigh on the moon?
Fg = m*g = 100kg * 1.6 m/s2 = 160N
We call this time the Period (T)
As you get farther away from an object (like the Earth), what happens to the force of gravity?
It gets smaller and smaller
In Henry Cavendish's experiment, what happened when two small masses on a rod were suspended in air next to two large masses?
The small masses moved towards the large masses
What is the centripetal force of an object that has a mass of 10kg, velocity of 5 m/s, and radius of motion of 10m?
25N
A 133kg man jumps out of an airplane on a newly discovered planet, and accelerates towards the ground at 15.3 m/s2. What is his weight on this new planet?
2035N
True/False. If the radius of some circular motion is larger, the object will travel farther in one rotation.
True
What is the Universal Gravitational Constant?
6.67 * 10-11
What is different about standing at the equator versus standing at the north pole in terms of circular motion?
At the equator, you have additional circular motion from the rotation of the Earth.
What is the centripetal force of an object that has a mass of 1000 g, velocity of 7.2 m/s, and radius of motion of 3m?
17.28N
Two planets are 15 million meters away from each other. Planet one is 6 million kg, Planet two is 8 million kg. What is the Force of Gravity between the two planets?
1.42 * 10-11 N
In circular motion, the object orbiting (traveling in a circle) has an acceleration in what direction?
Towards the center of the circle
Why doesn't the Moon crash into the Earth from the effect of Gravity?
It has a velocity, so it continues to 'fall around the Earth' and just keeps missing.
Who is credited with the discovery that planets and other objects in space follow the same laws of motion as on Earth?
Isaac Newton
What is the acceleration of an object with a circular velocity of 15 m/s, and a radius of motion of 8.9 m?
25.3 m/s2
Two planets are 5 million meters away from each other. Planet one is 8 million kg, Planet two is 15 million kg. What is the Force of Gravity between the two planets?
3.20 * 10-10 N
Why do the planets in the solar system have circular paths around the sun, instead of orbiting around each other?
Why do we call the International Space Station a "zero-gravity environment"? Is this accurate?
Because the astronauts feel 'weightless'. This is inaccurate. They still have weight (force of gravity), but feel no Normal Force.
1) What would happen to the I.S.S. if the Earth suddenly increased in mass?
2) What would happen if the Earth suddenly decreased in mass?
1) The I.S.S. would crash to the surface from the increased force of gravity
2) The I.S.S. would drift off into space and leave orbit
What is the centripetal force of a 13kg object, that is traveling in a 1.3m radius circle with a period of 1.9 seconds.
185N
DAILY DOUBLE!!!
When talking about space, you will often hear the phrase "space-time". This is the overall 'fabric' of the universe. Explain what happens to this 'fabric', when very massive objects (like planets) are present.
You have 3 minutes.
The fabric of space-time is actually warped or bent. Think about what happens to a stretched out sheet if you drop a marble in it. It bends.