A cup of tea/coffee transfers heat via conduction, convection and radiation.
Conduction:
- Heat transfer from a coffee to the spoon is in direct contact
- Inner part of the tea cup against hot liquid will transfer heat to the outer part and saucer.
Convection:
Movement of molecules within the coffee. Hot molecules of the tea at the middle of the drink will be eventually make their way to the outer part of the drink near the tea cup, where they will loose their heat.
Radiation:
Thermal radiation is the loss of heat from a solid object in to atmosphere via the release of electromagnetic radiation. So hot outer edge of the teacup loss the energy to its surroundings via thermal radiation.
Answer: The elevator must be accelerating.
Explanation:
As the tension force is opposing to the the force of gravity on the load which is hung vertically, and the tension force can adopt any value in order to comply with Newton's 2nd law, if the tension force is less than the force due to gravity, this means that all system is not in equilibrium, so it must be accelerating.
If we assume that the downward is the positive direction, we can write:
mg - T = ma
If T = 0.9 mg, ⇒ mg (1-0.9) =0.1 mg = m a ⇒a = 0.1 g , in downward direction.
Answer:
C
Explanation:
I got it right on the test !!
Answer:
Answered
Explanation:
u = 1.75 m/s
h = 15 m
Now, for the magnitude of velocity when hitting the deck
Using third equation of motion
v^2 - 1.75^2 = 2×9.8×15
v = 17.15 m/s
the velocity of sandal when it hits the deck is 17.15 m/s this the velocity of sandal relative to the ship
b) velocity relative to a stationary observer on shore
=
=17.23 m/s
To a person aboard the ship, they see the sandal land directly below the release point. A stationary observer on the outside sees the same thing, except the fact that the landing point has translated to the south.