Answer:
The correct option is;
A) Steel becomes too hot in the Sun and can burn the children
Explanation:
The properties of steel includes;
Low specific heat capacity, high thermal and electrical toughness, high hardness, high tensile strength, high yield strength, appreciable elongation, high fatigue strength, can easily corrode, high malleability and ability to creep
Therefore, due to the low specific heat capacity, which is 0.511 J/(g·°C) and high conductivity of steel which is about 32 W/(m·k), the temperature of the steel can rapidly rise and the hot steel surface can readily conduct the heat, (due to the temperature difference) to other bodies that come in contact
Answer:
c
because oil is preventing corrosion and rust
Answer:
A private plane pilot is a mid-level position.
Explanation:
The six pilot certifications in the US are as follows:
- Sport Pilot
- Recreational Pilot
- Private Plane Pilot
- Commercial Plane Pilot
- Flight Instructor
- Airline Transport Pilot
From this listing, it is evident that the Private Plane Pilot is in the mid of the line so it is a mid-level position.
Answer:
Time taken by the
diameter droplet is 60 ns
Solution:
As per the question:
Diameter of the droplet, d = 1 mm = 0.001 m
Radius of the droplet, R = 0.0005 m
Time taken for complete evaporation, t = 1 min = 60 s
Diameter of the smaller droplet, d' = 
Diameter of the smaller droplet, R' = 
Now,
Volume of the droplet, V = 
Volume of the smaller droplet, V' = 
Volume of the droplet ∝ Time taken for complete evaporation
Thus

where
t' = taken taken by smaller droplet


t' = 
Answer:
Option ‘a’ is the cheapest for this house.
Explanation:
Cheapest method of heating must have least cost per kj of energy. So, convert all the energy in the same unit (say kj) and take select the cheapest method to heat the house.
Given:
Three methods are given to heat a particular house are as follows:
Method (a)
Through Gas, this gives energy of amount $1.33/therm.
Method (b)
Through electric resistance, this gives energy of amount $0.12/KWh.
Method (c)
Through oil, this gives energy of amount $2.30/gallon.
Calculation:
Step1
Change therm to kj in method ‘a’ as follows:

$/kj.
Step2
Change kWh to kj in method ‘b’ as follows:

$/kj.
Step3
Change kWh to kj in method ‘c’ as follows:

$/kj.
Thus, the method ‘a’ has least cost as compare to method b and c.
So, option ‘a’ is the cheapest for this house.