Your answers for a), b), and c) are correct. Good work !
d). The high noise levels in Technology and PE are more of
a concern to the teachers than to the students because the
students are only in there for 1 or 2 periods a day, but the
Technology and PE teachers are in there ALL day.
e). Mr. Jones can't hear as high frequency as Jenny can because
he is much older than Jenny is. Sadly, even without damage due to
loud noise, the ability to hear high frequencies does decrease with age.
f). The wooden surfaces in the gym cause the gym to be louder
than it would be if it had carpet on the floor. Carpet ... and soft
walls and ceilings ... absorb a lot of the sound that hits them.
But hard surfaces don't absorb much of the sound that hits them,
so it just keeps bouncing around until it finally fades away.
You can see this easily ... just go into the gym at your school, clap
your hands once, and notice how long you keep hearing the sound
after you clap.
Answer:
C. Sunlight to electricity
Explanation:
Photo voltaic cells covert sunlight to the electricity. It absorbs the light from the sun and use that sunlight to create electric current. The number of photo voltaic cells are connected together in a solar panel to generate enough electricity to power up a home.
Answer:
true
Explanation:
The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed. For example, the carbon atom in coal becomes carbon dioxide when it is burned. The carbon atom changes from a solid structure to a gas but its mass does not change.
Answer:
1) 
is<u> positive.</u>
<u></u>
2) 
Explanation:
<h2><u>
Part 1:</u></h2>
<u></u>
The charged rod is held above the balloon and the weight of the balloon acts in downwards direction. To balance the weight of the balloon, the force on the balloon due to the rod must be directed along the upwards direction, which is only possible when the rod exerts an attractive force on the balloon and the electrostatic force on the balloon due to the rod is attractive when the polarities of the charge on the two are different.
Thus, In order for this to occur, the polarity of charge on the rod must be positive, i.e., is <u>positive.</u>
<u></u>
<h2><u>
Part 2:</u></h2>
<u></u>
<u>Given:</u>
- Mass of the balloon, m = 0.00275 kg.
- Charge on the balloon,
- Distance between the rod and the balloon, d = 0.0640 m.
- Acceleration due to gravity,
In order to balloon to be float in air, the weight of the balloom must be balanced with the electrostatic force on the balloon due to rod.
Weight of the balloon, 
The magnitude of the electrostatic force on the balloon due to the rod is given by
is the Coulomb's constant.
For the elecric force and the weight to be balanced,
I do believe the answer is land because the ocean/sea gets cold when its night. So the answer is land
