Answer:
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.
Since the outer plumage of the penguin can resist the flow of heat in the cold antarctic air they might gain a little of this heat to keep them warm by thermal convection.
<u>Explanation:</u>
- Convection is the circular movement that happens when hot air/liquid moves with molecules that were fast, making it less dense rises while the cold air/liquid drops down.
- Also, they follow the technique of standing together always in a group which further helps them to decrease the loss of heat between them.
- The plumage of penguin provides 80 percent of total insulation and is highly resistant to wind penetration.
Answer:
A. 2.8 m/s
Explanation:
Suppose that at the height of 0 m, the path of the pendulum is lowest.
If we use law of conservation of energy, the pendulum will have zero kinetic energy or K.E when it is at highest point, because K.E happens during movement of object and at the highest point all the energy will be P.E
P.E= mgh
Similarly, when the pendulum reaches at the lowest point, the height becomes zero and the P.E also becomes zero. Now all the energy will be K.E
K.E= 1/2 m v^2
In question, we are asked about the speed as the pendulum it reaches the lowest point of its path. Like we mentioned P.E will be zero at lowest point because of zero height. And also we will use law of conservation of energy because no energy has been lost from system.
K.E= P.E
1/2 m v^2 = mgh
Taking sq.root at both sides
v= Under root 2 gh
v=Under root 2x 9.8 m/s x0.4 m
v=Under root 7.84
v=2.8 m/sec
Hope it helps!
Answer:
The correct option is;
- 4x
Explanation:
From the inverse square law, as the distance from the source of a physical quantity increases, the intensity of the source is spread over an area proportional to the square of the distance of the object from the source
The inverse square law can be presented as follows;
As the distance, r, increases, the surface it covers also increases by the power of 2
Therefore, where the distance increases from r to 2·r, we have;
When, I, remain constant
The surface increases to 4·S by the inverse square law
Therefore, the correct option is 4 × x.
<span>The function of an electric motor is to change electrical energy
into
kinetic energy.
Even if you want to use the electric motor to give a heavy weight
a lot of potential energy, by lifting it up onto, say, the roof of a house,
you still have to use the motor to MOVE the weight. So you're still
giving it kinetic energy as an intermediate step..
</span>
