Answer:
False
Explanation:
Convection currents do not produce heat. In fact, convection current are a method of transfer of heat, not of production. Convection occurs when there is a fluid which is heated from bottom, from an external source of heat (such as a pot of boiling water over a flame): the bottom part of the fluid becomes warmer, and so less dense than the colder part, therefore it starts moving up, and it is replaced by the colder parts of the fluid, which go down. Later, these colder parts become warmer, so they start going up, being replaced by new colder parts, etc... in a cycle. This is known as convection current, but it requires an external source of heat, it does not produce heat by itself.
Answer:
A×B=C×D
500×0.5=250×X
250=250×X
X=250/250=1
X=1 m
Explanation:
note: if the force plus two, the distance will be half.
The correct option is C) The angle between the vectors is 120°.
Why?
We can solve the problem and find the correct option using the Law of Cosine.
Let A and B, the given two sides and R the resultant (sum),
Then,

So, using the law of cosines, we have:

Hence, we have that the angle between the vectors is 120°. The correct option is C) The angle between the vectors is 120°
Have a nice day!