Answer:

Explanation:
As we know that moment of force is given as

now we have


now from above formula we have

here we know that

so we have


<span>This is because Helium
has two valence electrons compared to Hydrogen which has only one. Helium has
more energy levels for an electron to jump thus more spectral lines to occur.
The spectral lines relating to each change of energy level would be more
grouped together and hence the greater chance of them falling in the visible
range.</span>
The velocity vector of the planet points toward the center of the circle is the following is true about a planet orbiting a star in uniform circular motion.
A. The velocity vector of the planet points toward the center of the circle.
<u>Explanation:</u>
Motion of the planet around the star is mentioned to be uniform and around a circular path. Objects in uniform circular motion motion has constant angular speed but the velocity of the object will not remain constant. Since the planet is in circular motion the direction of velocity vector at a particular point is tangential to the circular path at that particular point.
Thus at every point, the direction of velocity vector changes and this means the velocity is never constant. The objects in uniform circular motion has centripetal acceleration which means that velocity vector of the planet points toward the center of the circle.
Answer:
a) t = 0.528 s
b) D = 1.62 m
Explanation:
given,
speed of the baseball = 3.75 m/s
angle made with the horizontal = 35°
height of the roof edge = 2.5 m
using equation of motion



4.9 t² + 2.15 t - 2.5 = 0
on solving the above equation
t = 0.528 s
b) D = v cos θ × t
D = 3.75 × cos 35° ×0.528
D = 1.62 m
Answer:
v_{4}= 80.92[m/s] (Heading south)
Explanation:
In order to calculate this problem, we must use the linear moment conservation principle, which tells us that the linear moment is conserved before and after the collision. In this way, we can propose an equation for the solution of the unknown.
ΣPbefore = ΣPafter
where:
P = linear momentum [kg*m/s]
Let's take the southward movement as negative and the northward movement as positive.

where:
m₁ = mass of car 1 = 14650 [kg]
v₁ = velocity of car 1 = 18 [m/s]
m₂ = mass of car 2 = 3825 [kg]
v₂ = velocity of car 2 = 11 [m/s]
v₃ = velocity of car 1 after the collison = 6 [m/s]
v₄ = velocity of car 2 after the collision [m/s]
![-(14650*18)+(3825*11)=(14650*6)-(3825*v_{4})\\v_{4}=80.92[m/s]](https://tex.z-dn.net/?f=-%2814650%2A18%29%2B%283825%2A11%29%3D%2814650%2A6%29-%283825%2Av_%7B4%7D%29%5C%5Cv_%7B4%7D%3D80.92%5Bm%2Fs%5D)