Hey there!
Speed and velocity both:
1) Measure how fast something is moving
2) Both measured in miles per hour, meters/second, etc (rates)
However, there's a prime difference:
Different because:
1) Velocity is speed, but in a certain direction
2) Velocity is a vector
3) Velocity can be positive <em>or</em> negative, unlike speed.
I added another just in case you had a preference :)
Hope this helps!
I think it is called a loess. Please correct me if I am wrong.
I think it’s :answer choice c
Answer : The change in internal energy is, 900 Joules.
Solution : Given,
Heat given to the system = +1400 J
Work done by the system = -500 J
Change in internal energy is equal to the sum of heat energy and work done.
Formula used :

where,
= change in internal energy
q = heat energy
w = work done
As per question, heat is added to the system that means, q is positive and work done by the system that means, w is negative.
Now put all the given values in the above formula, we get

Therefore, the change in internal energy is 900 J.
The change in internal energy depends on the heat energy and work done. As we will change in the heat energy and work done, then changes will occur in the internal energy. Hence, the energy is conserved.