<span>So we want to know which of the following is the best representation of converting potential energy into kinetic energy. The correct answer is C. A roller coaster rounds a curve to climb the next hill. So before he climbed the hill, the roller coaster had kinetic energy which he used to climb to the hill. Then the potential energy he has on the hill can again be transformed into kinetic energy when he will go down hill. </span>
Answer:
we could use the formula, v=u+at,
65=25+a (10), a=4 , since the motion is declerating we have a=-4 m/s2
Answer:
(a) 41.75m/s
(b) 4.26s
Explanation:
Let:
Distance, D = 89m
Gravity,
= 9.8 m/
Initial Velocity,
= 0m/s
Final Velocity,
= ?
Time Taken,
= ?
With the distance formula, which is
D =
+ 
and by substituting what we already know, we have:
89 =
×9.8×
With the equation above, we can solve for
:

Now that we have solved
, we can use the following velocity formula to solve for
:
, where
is also equals to
, so we have

By substituting
,
, and
,
We have:

Answer: 
Explanation:
The equation to calculate the center of mass
of a particle system is:

In this case we can arrange for one dimension, assuming the geometric center of the Earth and the ladder are on a line, and assuming original center of mass located at the Earth's geometric center:

Where:
is the mass of the Earth
is the mass of 1 billion people
is the radius of the Earth
is the distance between the center of the Earth and the position of the people (2 m above the Earth's surface)

This is the displacement of Earth's center of mass from the original center.