Answer:
<h2>2.4</h2>
Explanation:
<h2><em>Hope it help mark as Brainlist</em></h2>
Answer:
The bottom/center of the pendulum
Explanation:
As it swings, the pendulum will have maximum potential energy at the top of its arc.
As it comes back towards the center that potential energy will convert into kinetic energy until it reaches the middle of its swing (when the pendulum is fully vertical) where all potential energy has been converted into kinetic energy.
This is when the kinetic energy is the highest
As it begins to move away from the center of its arc, that kinetic energy will convert into potential energy again, and the process repeats
We have the equation of motion 
, where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.
Here displacement = 135 m, Initial velocity = 0 m/s, acceleration = 9.81 
Substituting
A box falls out of a stationary helicopter hovering 135 m above the ground will take 5.25 seconds to reach the ground.
Answer:
It's impossible for an ideal heat engine to have non-zero power.
Explanation:
Option A is incomplete and so it's possible.
Option B is possible
Option D is related to the first lae and has nothing to do with the second law.
Hence, the correct option is C.
The ideal engine follows a reversible cycle albeit an infinitely slow one. If the work is being done at this infinitely slow rate, the power of such an engine is zero.
We can also stat the second law of thermodynamics in this manner;
It is impossible to construct a cyclical heat engine whose sole effect is the continuous transfer of heat energy from a colder object to a hotter one.
This statement is known as second form or Clausius statement of the second law.
Thus, it is possible to construct a machine in which a heat flow from a colder to a hotter object is accompanied by another process, such as work input.
