Answer:
System D --> System C --> System A --> System B
Explanation:
The gravitational force between two masses m1, m2 separated by a distance r is given by:
where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:
System A has masses m and m separated by a distance r:
system B has masses m and 2m separated by a distance 2r:
system C has masses 2m and 3m separated by a distance 2r:
system D has masses 4m and 5m separated by a distance 3r:
Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:
System D --> System C --> System A --> System B
The bike is maintaining "constant velocity". He's moving at 15 m/s when we see him for the first time, 15 m/s later that day, and 15 m/s next week.
The car starts from zero, and goes 4.0 m/s FASTER each second. After one second, it's going 4.0 m/s. After 2 seconds, it's going 8 m/s. And after 3 seconds, it's going 12 m/s.
This is the point at which the question wants us to compare them ... 3 seconds. The bike is moving at 15 m/s and the car has sped up to 12 m/s. <em>The bike is moving faster than the car.</em>
If we hung around and kept watching for another second, the car would then be moving at 16 m/s, and would be moving faster than the bike. But we lost interest after answering the question, and we left at 3 seconds.
I think the word you want is "incandescent".
The planet would stay in the same orbit but start revolving faster.
(Its year would get shorter.)
Answer: 20.765 m/s
Explanation:
This problem can be solved by the conservation of energy principle, this means the initial energy 
must be equal to the final energy 
:
(1)
Where each energy is the sum of kinetic energy 
and potential energy 
:
(2)
Where:
Being 
your mass and 
your initial velocity, since the roller coaster sterted from rest.
Being 
the acceleration due gravity and 
your initial height
Being 
your final velocity
Being 
your final height
Rewritting (2):
(3)
(4)
Isolating :
(5)
(6)
Finally:
This is your spedd when you arrive at 3 m height
