Answer:
Q1. C
Q2 and Q3 are correct.
Explanation:
Since F=ma, and the force is a constant,
for the greatest acceleration, the mass of the ball must be the least.
Thus ball C has the greatest acceleration.
Let's check:
A) F=ma
a=F/m
a= F/68
B) a=F/72
C) a= F/64 (✓)
The smaller the denominator, the larger the value of a.
(Think: 1/2 >1/3)
Answer: The initial temperature of the iron was 
Explanation:

As we know that,

.................(1)
where,
q = heat absorbed or released
= mass of iron = 360 g
= mass of water = 750 g
= final temperature = 
= temperature of iron = ?
= temperature of water = 
= specific heat of iron = 
= specific heat of water= 
Now put all the given values in equation (1), we get
![-360\times 0.450\times (46.7-x)=[750\times 4.184\times (46.7-22.5)]](https://tex.z-dn.net/?f=-360%5Ctimes%200.450%5Ctimes%20%2846.7-x%29%3D%5B750%5Ctimes%204.184%5Ctimes%20%2846.7-22.5%29%5D)

Therefore, the initial temperature of the iron was 
A quantitative observation is not necessarily more useful than a non-quantitative one. However, quantitative observations do allow one to find trends.
(a), the sun rising is a non-quantitative observation.
(b), knowledge of the numerical relationship between the weight on the Moon and on Earth, is a quantitative observation.
(c), watching ice float on water does not involve a measurement; therefore, it must be a qualitative observation.
(d) the fact that we know that the water pump won’t work for depths more than 34 feet makes it quantitative. Again, seeing numbers is a giveaway that it’s a quantitative <span>observation. Quantitative is where you deal with numbers.</span>
Answer: D?
Explanation: The mitochondrion (plural mitochondria) is a membrane-bound organelle found in the cytoplasm of eukaryotic cells. It is the power house of the cell; it is responsible for cellular respiration and production of (most) ATP in the cell.