Answer:
Water and Oxides such as iron oxide or rust
Explanation:
Answer:
B.The force of friction between the block and surface will decrease.
Explanation:
The force of friction is given by
where 
is the coefficient of friction and 
is the normal force.
When the student pulls on the block with force 
at an angle 
, the normal force on the block becomes
and hence the frictional force becomes
.
Now, as we increase , 
increases which as a result decreases the normal force 
, which also means the frictional force decreases; Hence choice B stands true.
<em>P.S: Choice D is tempting but incorrect since the weight </em>
<em> is independent of the external forces on the block. </em>
Answer:The answer is B
Explanation:
A generator produces electricity. Energy enters the system (generator) as kinetic energy. It is converted into electrical energy, which can run electrical appliances. Some energy is always wasted as heat and sound. Therefore, Choice B is the best answer.
Answer:
Form of energy: Example
1. Light energy: Electromagnetic radiation
2. Nuclear energy: Nuclear fission
3. Chemical energy: Energy stored in plant matter
4. Electrical energy: Lightning
5. Thermal energy: A hot surface
6. Sound energy: A tuning fork
7. Solar energy: Energy from the Sun
8. Mechanical energy: A moving vehicle
