A direct current
this is a current that only flows in one direction
Mac and Keena are experimenting with pulses on a rope. Mac vibrates one end up and down while Keena holds the other end. This creates a pulse which they observe moving from end to end. How does the position of a point on the rope before the start of the pulse compare to its position after the pulse passes? Explain your reasoning.
Explanation:
Equation for energy balance will be as follows.


Hence, 
Therefore, we will calculate the final temperature as follows.

= 868.03 R
Now, we will calculate the mass as follows.
m = 
= 
= 1.031 lbm
Hence,

Putting the values into the above equation as follows.


= 655.2 Btu
Thus, we can conclude that work done by paddle wheel is 655.2 Btu.
<u>Answer:</u>
The height of ramp = 124.694 m
<u>Explanation:</u>
Using second equation of motion,

From the question,
u = 31 m/s; s = 156.3 m, a=0
substituting values

t = 
= 5.042 s
Similary, for the case of landing
t = 5.042 s; initial velocity, u =0
acceleration = acceleration due to gravity, g = 9.81 
Substituting in 

h = 124.694 m
So height of ramp = 124.694 m