<span>Mass of the copper penny m = 2.6 g
Atomic mass of copper = 63.55, Atomic number = 29,
So the number of neutrons = Atomic mass - Atomic number = 63 - 29 = 34
a. Neutron mass = 34 x (2.6 / 63.55) = 1.4 grams
Copper atoms per mole = 6.040 x 10^23 atoms/mol
moles of copper = 2.6 / 63.06 = 0.04123 mol
Total atoms in the copper = 6.040 x 10^23 atoms/mol x 0.04123 mol = 0.25 x 10^23 atoms
Number of electrons in the copper = 29 per atom
Mass of the electron = 9.085 x 10^-28 g
b. Electron mass = 0.25 x 10^23 x 29 x 9.085 x 10^-28 = 65.86 x 10^-5 g</span>
Answer:
scratching a surface to make it rougher
increasing the size of a flying object
adding extra weight to an object
Explanation:
Before going to solve this question first we have to understand specific heat capacity of a substance .
The specific heat of a substance is defined as amount of heat required to raise the temperature of 1 gram of substance through one degree Celsius. Let us consider a substance whose mass is m.Let Q amount of heat is given to it as a result of which its temperature is raised from T to T'.
Hence specific heat of a substance is calculated as-
![c= \frac{Q}{m[T'-T]}](https://tex.z-dn.net/?f=c%3D%20%5Cfrac%7BQ%7D%7Bm%5BT%27-T%5D%7D)
Here c is the specific heat capacity.
The substance whose specific heat capacity is more will take more time to be heated up to a certain temperature as compared to a substance having low specific heat which is to be heated up to the same temperature.
As per the question John is experimenting on sand and water.Between sand and water,water has the specific heat 1 cal/gram per degree centigrade which is larger as compared to sand.Hence sand will be heated faster as compared to water.The substance which is heated faster will also cools faster.
From this experiment John concludes that water has more specific heat as compared to sand.

Explanation
the density of an object is given by:

Step 1
find the volume of the bar
a)find the volume of the rectangular bar.
the volume of a rectangular prism is given by:

replace

Step 2
now,
Let

replace in the formula

therefore, the answer is

I hope this helps you
It would be static friction which is what you have to overcome when an object is not in motion. When you move an object friction works against it like gravity and air resistance. I hope this helps!