Answer:
B
Explanation:
This happens because adding salt to the water decreases Its density. When the density of the water matches that of the egg, the egg becomes neutrally buoyant and floats.
The weight of the egg becomes equal to the upward buoyant force by the water on to the egg and hence, the egg floats.
Answer:
Its a parallel connection
Explanation:
The bulbs aren't in one line but two different parts, which makes it a parallel connection instead of a series connection.
I can confirm it is not b.
Answer:
W= 4.4 J
Explanation
Elastic potential energy theory
If we have a spring of constant K to which a force F that produces a Δx deformation is applied, we apply Hooke's law:
F=K*x Formula (1): The force F applied to the spring is proportional to the deformation x of the spring.
As the force is variable to calculate the work we define an average force
Formula (2)
Ff: final force
Fi: initial force
The work done on the spring is :
W = Fa*Δx
Fa : average force
Δx : displacement
:Formula (3)
: final deformation
:initial deformation
Problem development
We calculate Ff and Fi , applying formula (1) :


We calculate average force applying formula (2):

We calculate the work done on the spring applying formula (3) : :
W= 11N*(0.7m-0.3m) = 11N*0.4m=4.4 N*m = 4.4 Joule = 4.4 J
Work done in stages
Work is the change of elastic potential energy (ΔEp)
W=ΔEp
ΔEp= Epf-Epi
Epf= final potential energy
Epi=initial potential energy




W=ΔEp= 5.39 J-0.99 J = 4.4J
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