Answer:
310.5 J
Explanation:
The total work done by Martha is equal to the increase in gravitational potential energy of the package, which is equal to

where
(mg) = 45 N is the weight of the package
is the increase in height of the package
The package is carried up 3 flights of stairs, each one with a height of 2.3 m, so the total increase in heigth is

And so, the work done by Martha is

A. Discovering a quick way to handle a new problem
Answer:
6.88 mA
Explanation:
Given:
Resistance, R = 594 Ω
Capacitance = 1.3 μF
emf, V = 6.53 V
Time, t = 1 time constant
Now,
The initial current, I₀ = 
or
I₀ = 
or
I₀ = 0.0109 A
also,
I = ![I_0[1-e^{-\frac{t}{\tau}}]](https://tex.z-dn.net/?f=I_0%5B1-e%5E%7B-%5Cfrac%7Bt%7D%7B%5Ctau%7D%7D%5D)
here,
τ = time constant
e = 2.717
on substituting the respective values, we get
I = ![0.0109[1-e^{-\frac{\tau}{\tau}}]](https://tex.z-dn.net/?f=0.0109%5B1-e%5E%7B-%5Cfrac%7B%5Ctau%7D%7B%5Ctau%7D%7D%5D)
or
I =
or
I = 0.00688 A
or
I = 6.88 mA
Answer:
a) Due to the characteristic that a converging lens focuses light rays from infinity and parallel to its main axis. Therefore, the lens should be placed at a distance "f" from the film, in this way it will form the image of the object placed at infinity in said film.
b) Since the converging lens produces an image of an object placed at a distance of 2f, the lens must be placed at the same distance (2f), so that this object that is placed at a distance of 2f is focused.
Explanation:
B.Radiation, Because the heat is Radiating of of the burner. xD