A train travels 225 kilometers in 2.5 hours . what's the trains average speed
2 answers:
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Answer:
Kinetic energy cannot be negative
potential energy is a reference dependent quantity and it can be positive as well as negative both
Since potential energy is defined only for conservative force so it can not be found for friction force
Explanation:
Kinetic energy of an object is given by the formula
here we know that
m = mass of object that can not be negative
v = speed of the object and since its square is given here so it can not be negative
so Kinetic energy is always positive
potential energy is given as the energy due to the virtue of the position of object
so it is
so potential energy is a reference dependent quantity and it can be positive as well as negative both
Since potential energy is defined only for conservative force so it can not be found for friction force
Answer:
Explanation:
Satellites experiment a force given by Newton's Gravitation Law:
where M is Earth's mass, m the satellite's mass, r the distance between their gravitational centers and G the gravitational constant.
We also know from Newton's 2nd Law that <em>F=ma, </em>so putting both together we will have:
If we are on the surface of the Earth, the acceleration would be g and (Earth's radius):
Which we will write as:
If we are on orbit the acceleration is centripetal (), so we have:
And if this orbit has a radius we have: