Answer:d
Explanation:
Spring is compressed to a distance of x from its equilibrium position
Work done by block on the spring is equal to change in elastic potential energy
i.e. Work done by block 
therefore spring will also done an equal opposite amount of work on the block in the absence of external force
Thus work done by spring on the block 
Thus option d is correct
Answer:

Explanation:
first write the newtons second law:
F
=δma
Applying bernoulli,s equation as follows:
∑
Where,
is the pressure change across the streamline and
is the fluid particle velocity
substitute
for {tex]γ[/tex] and
for 

integrating the above equation using limits 1 and 2.

there the bernoulli equation for this flow is 
note:
=density(ρ) in some parts and change(δ) in other parts of this equation. it just doesn't show up as that in formular
Answer:
B.
Explanation:
One of the ways to address this issue is through the options given by the statement. The concepts related to the continuity equation and the Bernoulli equation.
Through these two equations it is possible to observe the behavior of the fluid, specifically the velocity at a constant height.
By definition the equation of continuity is,

In the problem
is
, then


<em>Here we can conclude that by means of the continuity when increasing the Area, a decrease will be obtained - in the diminished times in the area - in the speed.</em>
For the particular case of Bernoulli we have to


For the previous definition we can now replace,


<em>Expressed from Bernoulli's equation we can identify that the greater the change that exists in pressure, fluid velocity will tend to decrease</em>
The correct answer is B: "If we increase A2 then by the continuity equation the speed of the fluid should decrease. Bernoulli's equation then shows that if the velocity of the fluid decreases (at constant height conditions) then the pressure of the fluid should increase"
Answer:
35mA
Explanation:
Hello!
To solve this problem we must use the following steps
1. Find the electrical resistance of the metal rod using the following equation

WHERE
α=
metal rod resistivity=2x10^-4 Ωm
l=leght=2m
A= Cross-sectional area

solving

2. Now we model the system as a circuit with parallel resistors, where we will call 1 the metal rod and 2 the man(see attached image)
3.we know that the sum of the currents in 1 and 2 must be equal to 5A, by the law of conservation of energy
I1+I2=5
4.as the voltage on both nodes is the same we can use ohm's law in resitance 1 and 2 (V=IR)
V1=V2
(0.14I1)=2000(i2)
solving for i1
I1=14285.7i2
5.Now we use the equation found in step 3
14285.7i2+i2=5
