Here is the answer. Two sources of Earth's energy that are not produced would be Cosmic rays and Tidal Energy. Cosmic rays <span>are high-energy protons and atomic nuclei that come from outside the solar system. Whereas, tidal energy is the energy produced by both the moon (2/3) and the sun (1/3). Hope this answers your question.</span>
if we are walking on a perfectly smooth ground which has no friction our force would simply cancel out the force reverted by the ground and we would fall.
We need it to help push out feet off the ground
Hope those helps :)
Answer:
a. 
Explanation:
The equation of the forces along the directions parallel and perpendicular to the slope are:
- Along the parallel direction:
where
:
m = 6.0 kg is the mass of the box
g = 9.8 m/s^2 the acceleration of gravity
is the angle of the slope
is the coefficient of friction
R is the normal reaction
a is the acceleration
- Along the perpendicular direction:
From the 2nd equation, we get an expression for the reaction force:
And substituting into the 1st equation, we can find the acceleration:
Solving for a,
Answer: D. 0.29 m
Explanation:
We will use the following equations to describe the leap of the cat:
(1)
(2)
Where:
is the height of the cat
is the cat's initial velocity

is the acceleration due gravity
is the time
is the y-component of the velocity
Now the cat will have its maximum height
when
. So equation (2) is rewritten as:
(3)
Finding
:
(4)
(5)
(6)
Substituting (6) in (1):
(7)
Finally:
(8)
Answer:
The mass of the gold bar is 1,544 g
Explanation: