Answer:
net force is positive downward..B
Question no. 1. Compare the planets Mars and Saturn. Describe how their common characteristics are similar:
Answer: Our solar system is located in the outer spiral arm of the milky way galaxy. our solar system has one sun and nine revolving planets and . namely
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
- Pluto (small planet usually refer as dwarf)
Each star has its on moon/moons and has its own characteristics i.e , planet must be a celestial body , must have orbit around sun, have enough mass for self gravity, big enough to have gravity that clear its path from other same size object close to its orbit around sun.
Mars is the fourth from the sun and sixth is the Saturn from the sun in our solar system.
<u>Common in Characteristics of Mars and Saturn:</u>
- Mars and Saturn both have celestial body.
- Mars and Saturn both have enough mass for the gravity to get rid of rigid body forces.
- Mars and Saturn both revolve around the sun in their own orbits.
- Mars is the second smallest in the solar system while Saturn is second largest in the solar system.
- Mars and Saturn both have their own moons. Mars has two while Saturn has 83 moons
- Mars and Neptune both do not support life.
Question no. 2. Compare the planets Earth and Neptune. Describe how are they different from each other
Answer:
Earth our home planet is the third from the sun and Neptune on the other hand is the eighth from the sun in the solar system.
<u>Common differences between Earth and Neptune</u>
- Earth is the terrestrial planet while Neptune (Ice giant) is the Jovian planet.
- Earth has no ring around it, Neptune has ring around it.
- Earth is closer to the sun and Neptune is far distant from the sun.
- Earth consists of rocks and metals on the other hand Neptune contain gases
- Earth is smaller than the Neptune in the solar system.
- Earth rotates slower and Neptune rotates faster.
Answer:
At 81. 52 Deg C its resistance will be 0.31 Ω.
Explanation:
The resistance of wire =
Where 
=Resistance of wire at Temperature T
= Resistivity at temperature T ![=\rho_0 \ [1 \ + \alpha\ (T-T_0\ )]](https://tex.z-dn.net/?f=%3D%5Crho_0%20%5C%20%5B1%20%5C%20%2B%20%5Calpha%5C%20%28T-T_0%5C%20%29%5D)
Where 
l=Length of the wire
& A = Area of cross section of wire
For long and thin wire the resistance & resistivity relation will be as follows
![\frac{0.25}{0.31}=\frac{1}{[1+\alpha(T-20)]}](https://tex.z-dn.net/?f=%5Cfrac%7B0.25%7D%7B0.31%7D%3D%5Cfrac%7B1%7D%7B%5B1%2B%5Calpha%28T-20%29%5D%7D)
T = 81.52 Deg C
The answer is False because HIV spreads through contact between HIV-infected blood or blood-contaminated body fluids and broken skin, wounds, or mucous membranes. Deep, open-mouth kissing if both partners have sores or bleeding gums and blood from the HIV-positive partner enters the HIV-negative partner's bloodstream.
Answer:
W = ½ m v²
Explanation:
In this exercise we must solve it in parts, in a first part we use the conservation of the moment to find the speed after the separation
We define the system formed by the two parts of the rocket, therefore the forces during internal separation and the moment are conserved
initial instant. before separation
p₀ = m v
final attempt. after separation
= m /2 0 + m /2 v_{f}
p₀ = p_{f}
m v = m /2 
v_{f}= 2 v
this is the speed of the second part of the ship
now we can use the relation of work and energy, which establishes that the work is initial to the variation of the kinetic energy of the body
initial energy
K₀ = ½ m v²
final energy
= ½ m/2 0 + ½ m/2 v_{f}²
K_{f} = ¼ m (2v)²
K_{f} = m v²
the expression for work is
W = ΔK = K_{f} - K₀
W = m v² - ½ m v²
W = ½ m v²
