Answer:
v = 0.41 m/s
Explanation:
- In this case, the change in the mechanical energy, is equal to the work done by the fricition force on the block.
- At any point, the total mechanical energy is the sum of the kinetic energy plus the elastic potential energy.
- So, we can write the following general equation, taking the initial and final values of the energies:

- Since the block and spring start at rest, the change in the kinetic energy is just the final kinetic energy value, Kf.
- ⇒ Kf = 1/2*m*vf² (2)
- The change in the potential energy, can be written as follows:

where k = force constant = 815 N/m
xf = final displacement of the block = 0.01 m (taking as x=0 the position
for the spring at equilibrium)
x₀ = initial displacement of the block = 0.03 m
- Regarding the work done by the force of friction, it can be written as follows:

where μk = coefficient of kinettic friction, Fn = normal force, and Δx =
horizontal displacement.
- Since the surface is horizontal, and no acceleration is present in the vertical direction, the normal force must be equal and opposite to the force due to gravity, Fg:
- Fn = Fg= m*g (5)
- Replacing (5) in (4), and (3) and (4) in (1), and rearranging, we get:


- Replacing by the values of m, k, g, xf and x₀, in (7) and solving for v, we finally get:

Answer:I=12 A
Explanation:
Given
Resistance 
Voltage 
According to ohm's law current through a conductor is directly proportional to the voltage applied.


where V=Voltage
I=Current
R=resistance



<span>coefficient
Let's look at the 3 possibilities and see what they are for </span>3H₂O₂ coefficient - This is used to indicate that multiple molecules are used for the formula. In 3H₂O₂ that indicates that we are talking about 3 molecules of H₂O₂ subscript - This is a small number set in a smaller font and placed low to the elements. It indicates the number of each type of atom in the compound. For the formula 3H₂O₂ there are 2 subscripts. Both of them being the number "2" set small and low just after the letters H and O. Those subscripts indicate that there are 2 hydrogen and 2 oxygen atoms per molecule.
element - This is the abbreviation for the elements used in the compound. In <span>3H₂O₂</span> there are 2 different elements. H to indicate hydrogen, and O to indicate oxygen.