What’s the question or problem ?
Answer:
Part a)

Part b)

Explanation:
Part a)
For force conditions of two blocks we will have


now from above equations we have


now we know that


now from above equation we have


Part b)
When heavier block is removed and F = 908 N is applied at the end of the string then we have



Answer:
(A) ratio of electric force to weight will be 
(b) Electric field will be 
Explanation:
We have given mass of bee = 100 mg = 
Charge on bee 
Electric field E = 100 N/C
Weight of the bee 
Electric force on the bee 
So the ratio of electric force on the bee and weight is 
(B) To hold the bee in air electric force must be equal to weight of bee
So 


Answer:
1716.75 J
Explanation:
<u>Step </u><u>1</u><u>:</u> First check what we are provided with. As per given question we have:
mass (m) = 70 kg, height (h) = 2.5 m and acceleration due to gravity (g) = 9.81 m/s².
<u>Step</u><u> </u><u>2</u><u>:</u> Check what we are asked to find out.
Work done = Change in Potential energy
The stuff required to solve this question is potential energy. Using the formula: P = mgh. Where P is Potential energy, m is mass, g is acceleration due to gravity and h is height.
<u>Step</u><u> </u><u>3</u><u>:</u> Substitute the known values in the above formula.
→ P = 70 × 2.5 × 9.81
→ P = 1716.75 J
Hence, the work done against the force of gravity is 1716.75 J.
<span>Use Charles' Law:
v1/T1 = v2/T2
88.2/(273+35) = v2/(273+155)
where v2 is the new volume.
I hope this helps!!!</span>