Answer:
V_vap = 161.2 L
Explanation:
The total mass of the aluminum rod is given as;
m = ρ∙V = ρ∙L∙A
Where;
ρ is density = 2700 kg/m³
L is length = 3.3m
A is cross sectional area = 3.8 cm² = 3.8 x 10⁻⁴ m²
Thus;
m = 2700kg/m³•3.3m•3.8 × 10⁻⁴m²
= 3.3858kg
By cooling down the submerged half of the aluminum rod releases an heat amount of
Q = (1/2)∙m∙cp∙∆T
Where;
cp is specific heat of aluminum aluminum = 900 J/kg
∆T is change in temperature = 274 - 4.2 = 269.8 K
Thus;
Q = (1/2)•3.3858•900•(269.8)
= 411069.978 J
The liquid absorbs this heat and vaporizes partially, such that the heat equals vaporized mass times latent heat of vaporization:
Q = m_vap•∆h_vap
Making m_vap the subject;
m_vap∙ = Q/∆h_vap
Where ∆h_vap is latent heat of vaporization given as 20900J/kg
Thus,
m_vap∙ = 411069.978/20900
= 19.668 kg
Let's divide this mass by the density of liquid helium and we get the liquid volume which has vaporized:
V_vap∙= m_vap/ρ
V_vap∙ = 19.668/122
V_vap∙ = 0.1612 m³
Converting to litres;
V_vap = 0.1612 x 1000
V_vap = 161.2 L
Answer:
s = 589.3 m
Explanation:
Let the truck and car meet at a distance = s m
The truck is moving at constant velocity = v
so s= v * t ---------- (1)
car:
Vi = 0 m/s
a = 3.9 m/s²
s = Vi* t + 1/2 a t²
s= 0 * t + 1/2 a t²
s = 1/2 a t² ----------- (2)
compare equation (1) and equation (2)
s= v * t = 1/2 a t²
⇒ v * t = 1/2 a t²
⇒ t = 2 * v/ a
⇒ t = (2 * 33.9 )/ 3.9
⇒ t = 17. 38 s
Now
from equation (1)
s= v * t
s= 33.9 * 17.38
⇒ s = 589.3 m
Answer:
Option (A)
Explanation:
The green plants are capable of synthesizing their own food, in the presence of sunlight, CO₂ and water, and in return, liberates food and oxygen (O₂). This process is known as photosynthesis. This process is possible due to the presence of chlorophyll pigments on the plant leaves.
These green plants are also known as producers, because they are able to generate food for the consumers.
Thus, the correct answer is option (A).
multiply grav pull by mass of astro maybe with a calculator
