Answer:
Explanation:
Small grains are negatively charged by the wind while big grains is positively charged and remains at the ground . This process creates an electric field due to the presence of oppositely charged particles.
When ever electric field exists it is directed from a positive charge to a negative charge so the here electric field is towards an upwards direction.
The quantity that has a magnitude of zero when the ball is at the highest point in its trajectory is
the vertical velocity.
In fact, the motion of the ball consists of two separate motions:
- the horizontal motion, on the x-axis, which is a uniform motion with constant velocity

, where

- the vertical motion, on the y-axis, which is a uniformly accelerated motion with constant acceleration

directed downwards, and with initial velocity

. Due to the presence of the acceleration g on the vertical direction (pointing in the opposite direction of the initial vertical velocity), the vertical velocity of the ball decreases as it goes higher, up to a point where it becomes zero and it reverses its direction: when the vertical velocity becomes zero, the ball has reached its maximum height.
To solve this problem, we must imagine that Jim’s initial
position, the position of the rock, and Jim’s final position all connects to
form a triangle. Now we can imagine that the triangle is a right triangle with
the 90° angle on the initial position.
The angle of 30° is directly opposite to the length of his
total stride while the width of the river is the side adjacent to the angle.
Therefore can use the tan function to solve for the width of the river:
tan θ = opposite side / adjacent side
tan 30 = total stride distance / width of river
where total stride distance = 65 * 0.8 = 52 m
width of river = 52 m / tan 30
<span>width of river = 90.07 m</span>
Answer:
Relative population is 2.94 x 10⁻¹⁰.
Explanation:
Let N₁ and N₂ be the number of atoms at ground and first excited state of helium respectively and E₁ and E₂ be the ground and first excited state energy of helium respectively.
The ratio of population of atoms as a function of energy and temperature is known as Boltzmann Equation. The equation is:
= 
= 
Here g₁ and g₂ be the degeneracy at two levels, K is Boltzmann constant and T is equilibrium temperature.
Put 1 for g₁, 3 for g₂, -19.82 ev for (E₁ - E₂) and 8.6x10⁵ ev/K for K and 10000 k for T in the above equation.
= 
= 3.4 x 10⁹
= 2.94 x 10⁻¹⁰