**Answer: Ok, first lest see out problem.**

**It says it's a Long cylindrical charge distribution, So you can ignore the border effects on the ends of the cylinder.**

Also by the gauss law we know that E¨*2*pi*r*L = Q/ε0

where Q is the total charge inside our gaussian surface, that will be a cylinder of radius r and heaight L.

So Q= rho*volume= pi*r*r*L*rho

so replacing : E = (1/2)*r*rho/ε0

you may ask, ¿why dont use R on the solution?

since you are calculating the field inside the cylinder, and the charge density is uniform inside of it, you don't see the charge that is outside, and in your calculation actuali doesn't matter how much charge is outside your gaussian surface, so R does not have an effect on the calculation.

R would matter if in the problem they give you the total charge of the cylinder, so when you only have the charge of a smaller r radius cylinder, you will have a relation between r and R that describes how much charge density you are enclosing.

**Answer:**

The magnitude is 63 kg m²/s, and the direction is -k.

**Explanation:**

Plug the values into the equation:

L = m v×r

L = (3.0 kg) (<5 i + 3j> m/s × <2i − 3j> m)

Take the cross product. The cross product of two dimensional vectors is:

<v₁ i + v₂ j> × <r₁ i + r₂ j> = <(v₁ r₂ − v₂ r₁) k>

Therefore:

L = (3.0 kg) <((5)(-3) − (3)(2)) k m²/s>

L = (3.0 kg) <-21 k m²/s>

Multiply:

L = <-63 k kg m²/s>

The magnitude is 63 kg m²/s, and the direction is -k.

The amount of energy is ALWAYS conserved based on the law of conservation of energy. Therefore, the amount of energy will remain the same.

The horizontal speed has no effect on how long it takes to reach the ground.

A bullet shot from a gun and a bullet dropped from the front end of the gun

at the same time as the shot both hit the ground at the same time.

The number that counts is the height from which it fell . . . the 1.25 m.

I'll use this very useful formula:

Distance of free fall,

starting from rest = (1/2) · (gravity) · (time)²

1.25 m = (1/2) · (9.8 m/s²) · (time)²

Divide each side

by 4.9 m/s² : 1.25 m / 4.9 m/s² = time²

0.2551 sec² = time²

Square root each side: **0.505 sec = time**

It looks like the correct choice is approximately 'A'. (rounded)

**Answer:**

Radiation is the emission or transmission of energy in the form of waves.

**Explanation:**

.