The thermal efficiency of an engine is

where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
Answer:
a. They will be tie
b. Win the wood cylinder
Explanation:
a.
The both cylinders will reach the bottom at the same time notice the relation in the equation in indepent of the length and both have the same radius and the same rotational inertia.


So both will be tie
b.

The acceleration of the wood cylinder is larger than the acceleration of the brass cylinder so the cylinder of wood will reach the bottom first

So the wood win the race
Average speed = total distance traveled/total time taken
it is the total distance traveled in a total time the total distance is attained
A star with large luminosity would have a relatively low absolute magnitude. Absolute magnitude is a number that tells how bright a star is from the Earth. However, this scale is backwards and logarithmic, so having a large absolute magnitude value means that the star is faint.
Answer: option d.
Explanation:1) The
direction of the
field lines inform about the
sign of the charges.
The field lines <span>
extend from the positive charges to the negative charges, so you can conclude that the charge C is positve and both charge A and charge B are negative:
</span><span>
</span><span>
</span><span>Charge C: positive
</span><span>
</span><span>Charge A: negative
</span><span>
</span><span>Charge B: netative
</span>
2) The
density of the lines (number of lines in a region) inform about the
magnitude of the electric field.
Since the charges are at the same distance, the magnitude of the electric field informs directly about the magnitude of the force and that about the magnitude of the charges.
Since, there are the
double of lines between C and B than between C and A, the magnitude of
charge B is the double than the magnitud of charge A.
From the five options given (a throug e) the only that is consistent with that charges A and B have the same sign, that charge C has different sign, and that charge B is the double of charge A is: