Since the main objective of this experiment is to determine the effect of porosity on seedling growth that should be the only independent variable. In short, that is the only variable that should be different to ensure fair testing.
The answer should be B:
he plants seedlings in soils with different levels of porosity and equal levels of permeability.
Permeability is not what needs to be tested. If it changes, you may not be able to determine whether it was the porosity or permeability that cause changes.
Answer:
a) amount of kinetic energy converted to internal energy = 2.5 x 10 raised to power 7 Joule
b) Kinetic energy gained by the earth = 2.1 x 10-16J
c) All the kinetic energy is converted to internal energy and the energy is further converted to thermal energy hence the reason for the hotness at around where the meteorite strikes.
Explanation:
The detailed steps and appropriate application of the law of conservation of momentum is as shown in the attached file.
Answer:
μ = 0.408
Explanation:
given,
speed of the automobile (u)= 20 m/s
distance = 50 m
final velocity (v) = 0 m/s
kinetic friction = ?
we know that,
v² = u² + 2 a s
0 = 20² + 2 × a × 50

a = 4 m/s²
We know
F = ma = μN
ma = μ mg
a = μ g


μ = 0.408
hence, Kinetic friction require to stop the automobile before it hit barrier is 0.408
Answer:
The average rate of energy transfer to the cooker is 1.80 kW.
Explanation:
Given that,
Pressure of boiled water = 300 kPa
Mass of water = 3 kg
Time = 30 min
Dryness friction of water = 0.5
Suppose, what is the average rate of energy transfer to the cooker?
We know that,
The specific enthalpy of evaporate at 300 kPa pressure


We need to calculate the enthalpy of water at initial state


We need to calculate the enthalpy of water at final state
Using formula of enthalpy

Put the value into the formula


We need to calculate the rate of energy transfer to the cooker
Using formula of rate of energy

Put the value into the formula


Hence, The average rate of energy transfer to the cooker is 1.80 kW.