A physical change in something doesn't change what the it is. For example, if you break glass, it will still be glass. In a chemical change where there is a chemical reaction, a new thing is formed and energy is either given off or absorbed. For example, when you burn a log. The carbon in the log is reacting to the oxygen to create ashe and smoke
Answer:
a) 
, b) 
Explanation:
The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:
Where 
is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:
Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:
a) t = 50 s.
b) t = 100 s.
Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:
Since 
, then the angular velocity is equal to zero. Therefore:
<span>Venus is hotter due to the greenhouse effect: Venus has an atmosphere about ninety times thicker than that of Earth, and made almost entirely of carbon dioxide, which is one of the gasses that causes the greenhouse effect on Earth.</span>
Light energy is defined as how nature moves energy at an extremely rapid rate, and it makes up about 99% of the body's atoms and cells, and signal all body parts to carry out their respective tasks. An example of light energy is the movement of a radio signal.
