Answer:
Without any external forces a moving object will continue to move in a straight line. The gravitational force between the two objects will provide the centripetal force to keep the objects moving around one another.
1. satellite in orbit around the earth (motion of earth is negligible)
2. moon in orbit around the earth (center of motion several thousand miles
from center of earth)
3. earth in orbit around sun (center of rotation close to center of sun)
4. binary stars (if masses of stars are equal center of rotation is in middle)
Formula: s = d/t
s = speed
d = distance
t = time
Solve using the values we are given.
s = 300/40
s = 7.5m/s
Best of Luck!
It could prevent the key from sinking because the wood would float.
It floats because it weighs less than amount of water it would have to push out of the glass if it sank. Wood, cork, and ice are all less dense than water, and they float; rocks are more dense, so they sink. A key would also be more dense causing it to sink.
Hope this helps,
Davinia.
