Ans: Beat frequency =
= 4HzExplanation: The beat frequency is equal to the absolute value of the difference in frequency of the two waves. In other words, the number of beats per second is equal to the difference in frequency. It is due to the destructive and constructive interference. <span>According to this interference, sound will be soft or loud.
Hence. the formula is:
</span>Beat frequency =

<span>
Since,
</span>


Therefore,
Beat frequency =

=> Beat frequency =

-i
- Weight (W) = 110 N
- Acceleration due to gravity (g) = 9.8 m/s^2
- Let the mass of the object be m.
- By using the formula, W = mg, we get,
- 110 N = 9.8 m/s^2 × m
- or, m = 110 N ÷ 9.8 m/s^2
- or, m = 11.2 Kg
<u>Answer:</u>
<em><u>The </u></em><em><u>mass </u></em><em><u>of </u></em><em><u>the </u></em><em><u>object </u></em><em><u>is </u></em><em><u>1</u></em><em><u>1</u></em><em><u>.</u></em><em><u>2</u></em><em><u> </u></em><em><u>Kg.</u></em>
Hope you could get an idea from here.
Doubt clarification - use comment section.
Answer:
The final velocity of the cart is
Explanation:
From the question we are told that
The mass of the girl is 
The mass of the cart is 
The speed of the cart and kid(girl) is 
The final velocity of the girl is 
Let assume that velocity eastward is positive and velocity westward is negative (Note that if we assume vise versa it wouldn't affect the answer )
The total momentum of the system before she steps off the back of the cart
is mathematically evaluated as

substituting values


The total momentum after she steps off the back of the cart is mathematically evaluated as

Where
is the final velocity of the cart
substituting values


Now according to the law of conservation of momentum

So

=> 
Since the value is positive it implies that the cart moved eastward
I'm not sure about the rest but for question 2:
A theory is an attempt to come up with a big picture of all we know so far. It also drives future research as people do experiments to see if what the theory predicts actually happens. When experiments don’t support the theory, you have to change the theory and try again. That’s how science works. We come up with a “best guess” (theory), and then do research to test it’s accuracy. As we discover contradictions, we adjust the theory to take those into account, and then start testing the validity of the new theory.
What if when I find my product, I get the same compound as I did in my
reactant? For example, FeCl3 + HCl ->FeCl3 + HCl. Then something is
wrong. In this case, FeCl3 and HCl usually don't react. In very
concentrated solutions of HCl, the FeCl4^- or FeCl6^-3 ion can form.
In... There you go my friend