Answer:
Tying a 4 weight pound on a string is a potential energy because it is at rest but cutting it and letting it fall experiences a kinetic energy because it will be in motion.
Answer:
58.5 m
Explanation:
First of all, we need to find the total time the ball takes to reach the water. This can be done by looking at the vertical motion only.
The initial vertical velocity of the ball is

where
u = 21.5 m/s is the initial speed
is the angle
Substituting,

The vertical position of the ball at time t is given by

where
h = 13.5 m is the initial heigth
is the acceleration of gravity (negative sign because it points downward)
The ball reaches the water when y = 0, so

Which gives two solutions: t = 3.27 s and t = -0.84 s. We discard the negative solution since it is meaningless.
The horizontal velocity of the ball is

And since the motion along the horizontal direction is a uniform motion, we can find the horizontal distance travelled by the ball as follows:

Answer:
Many substances do not dissolve in water and that is because they are non-polar and do not interact well with water molecules. A common example is oil and water. Oil contains molecules that are non-polar, thus they do not dissolve in water.
Explanation:
Answer:12.8 ft/s
Explanation:
Given
Speed of hoop 
height of top 
Initial energy at bottom is

Where m=mass of hoop
I=moment of inertia of hoop
=angular velocity
for pure rolling 



Energy required to reach at top


Thus 512.2 m is converted energy is spent to raise the potential energy of hoop and remaining is in the form of kinetic and rotational energy

Therefore



Answer:
200 m/s
Explanation:
Given that,
A plane is moving due north, directly towards its destination. Its airspeed is 200 mph. A constant breeze is blowing from west to east at 60 mph.
We need to find the rate at which the plane is moving towards North. It can be given by :

Where
is the angle with the North

Hence, the plane is moving at a rate of 200 m/s.