Answer:
Matter have two essential types of properties, those are physical properties and chemical properties.
Explanation:
Answer:
Since opposite charges attract each other, the negatively charged electrons are attracted to the positively charged protons. ... Together, all of the electrons of an atom create a negative chargethat balances the positive charge of the protons in the atomic nucleus.
Explanation:
Answer:
B: Electrical - Heat
C: Electrical - kinetic
Explanation:
When the hair dryer is plugged to electric supply, electrical energy is converted into heat. When this electricity is circulated through a resistor, heat is now created in the form of losses which make the air around the resistors to be heated.
After that process, this electricity turns into kinetic energy because it forms Electric energy which moves the fan in order to create a flow with the air that's heated.
Answer:
3.26 secs
Explanation:
Diameter of sphere ( D )= 10 mm
T1 = 75°C
P = 1 atm
T∞ = 23°C
T2 = 35°c
Velocity = 10 m/s
<u>Determine how long it will take to cool the sphere to 35°C</u>
<em>Using the properties of copper and air given in the question</em>
Nu = 2 + (Re)^0.8 (Pr)^0.33
hd / k = 2 + ( vd/v )^0.8 (Pr)^0.33
∴ h ≈ 2594.7 W/m^2k
Given that :
(T2 - T∞) / ( T1 - T∞ ) = exp [ ( -hA / pv CP ) t ]
( 35 - 23 ) / ( 75 - 23 ) = exp [ - 2594.7 * 6 * t / 8933 * 387 * 10 * 10^-3 ]
= ln ( 12/52 ) = -1.466337069 = - 0.45032919 * t
∴ t ≈ 3.26 secs ( -1.466337069 / -0.45032919 )