Answer:
U² = 142.86 N
U¹ = 357.14 N
Explanation:
Taking summation of the moment about point A, we get the following equilibrium equation: (taking clockwise direction as positive)

where,
W = weight of boy = 500 N
U² = reaction ay B = ?
Therefore,

<u>U² = 142.86 N</u>
Now, taking summation of forces on the plank. Taking upward direction as positive, for equilibrium position:

<u>U¹ = 357.14 N</u>
Answer:
1 - amplification
3- actinide
5 - radioactive decay ( im not really sure on this one )
7- alternating current
Explanation:
It’s the wavelength I believe
B)
Doppler effect is about the apparent change in frequency. The change in pitch heard as an ambulance approaches you is an example of this
Answer:
i have absolutly no idea how to do it but i looked it up and your answer should be B. i could be wrong but thats what the web told me