<span>First law of thermodynamics. This conservation law states that energy cannot be created or destroyed but can be changed from one form to another. In essence, energy is always conserved but can be converted from one form into another. Like when an engine burns fuel, it converts the energy stored in the fuel's chemical bonds into useful mechanical energy and then into heat, or more specifically, the melting ice cubes. Yeast breaks down maltose into glucose to produce alcohol and Co2 in the fermentation process. This is a prime example of the 1st law of thermodynamics. No form of usable energy is really lost; it only changes from one form to another</span>
Answer:
When the ball is held motionless above the floor, the ball possesses only GPE energy.If the ball is dropped, its GPE energy decreases as it falls.If the ball is dropped, its KE energy increases as it falls.
Explanation:
If the ball is held motionless, then its kinetic energy is equal to zero, since kinetic energy depends on the velocity. And the ball is held above the ground, which means it possesses gravitational potential energy.
If the ball is dropped, its height will decrease, therefore its gravitational potential energy will decrease. Along the way, the ball will be in free fall, and therefore its velocity will increase, hence its kinetic energy.

Answer:
119.88 km/h
Explanation:
1500/45=33.3
use a m/s to km/h calculator
put in 33.3 for m/s and you will get 119.88 km/h.
119.88 km/h.
Answer:
45 N
Explanation:
F= ma (ie force is found by multiplying the mass of the object by its accerelation)
thus, F = 15 X 3 = 45 N
Answer:
(a) 0
(b) 10ML
(c) 
(d) 
Explanation:
(a) When hanging straight down. The child is at the lowest position. His potential energy with respect to this point would also be 0.
(b) Since the rope has length L m. When the rope is horizontal, he is at L (m) high with respect to the lowest swinging position. His potential energy with respect to this point should be

where g = 10m/s2 is the gravitational acceleration.
(c) At angle
from the vertical. Vertically speaking, the child should be at a distance of
to the swinging point, and a vertical distance of
to the lowest position. His potential energy to this point would be:

(d) at angle
from the horizontal. Suppose he is higher than the horizontal line. This would mean he's at a vertical distance of
from the swinging point and higher than it. Therefore his vertical distance to the lowest point is 
His potential energy to his point would be:
