Answer:
12.6 (3 sig. fig.)
Explanation:
(12^2 + 4^2)^1/2 = 12.6 (3 sig. fig.)
All the stars, spheres and galaxies that can be perceived nowadays
make up just 5 percent of the universe.
The former 95 percent is prepared of stuff stargazers can't see, notice or even
understand. These secretive substances are called dark energy and
dark matter. Experts determine their presence grounded on their gravitational
influence on what little bits of the universe can be perceived.
Answer:
1.56 J
Explanation:
The potential energy only depends on the vertical height from the ground level.
We consider the ground level to have zero P.E.
So when it is 2 m above the ground level,
P.E. = mgh
= 0.078×10×2
= 1.56 J
Answer:
K = -½U
Explanation:
From Newton's law of gravitation, the formula for gravitational potential energy is;
U = -GMm/R
Where,
G is gravitational constant
M and m are the two masses exerting the forces
R is the distance between the two objects
Now, in the question, we are given that kinetic energy is;
K = GMm/2R
Re-rranging, we have;
K = ½(GMm/R)
Comparing the equation of kinetic energy to that of potential energy, we can derive that gravitational kinetic energy can be expressed in terms of potential energy as;
K = -½U
