It shortens so that the tips reach faster
Yes a perch is a consumer.
To solve this problem it is necessary to apply the concepts related to Newton's second Law and the force of friction. According to Newton, the Force is defined as
F = ma
Where,
m= Mass
a = Acceleration
At the same time the frictional force can be defined as,

Where,
Frictional coefficient
N = Normal force (mass*gravity)
Our values are given as,

By condition of Balance the friction force must be equal to the total net force, that is to say



Re-arrange to find acceleration,



Therefore the acceleration the horse can give is 
Complete question:
In the movie The Martian, astronauts travel to Mars in a spaceship called Hermes. This ship has a ring module that rotates around the ship to create “artificial gravity” within the module. Astronauts standing inside the ring module on the outer rim feel like they are standing on the surface of the Earth. (The trailer for this movie shows Hermes at t=2:19 and demonstrates the “artificial gravity” concept between t= 2:19 and t=2:24.)
Analyzing a still frame from the trailer and using the height of the actress to set the scale, you determine that the distance from the center of the ship to the outer rim of the ring module is 11.60 m
What does the rotational speed of the ring module have to be so that an astronaut standing on the outer rim of the ring module feels like they are standing on the surface of the Earth?
Answer:
The rotational speed of the ring module have to be 0.92 rad/s
Explanation:
Given;
the distance from the center of the ship to the outer rim of the ring module r, = 11.60 m
When the astronaut standing on the outer rim of the ring module feels like they are standing on the surface of the Earth, then their centripetal acceleration will be equal to acceleration due to gravity of Earth.
Centripetal acceleration, a = g = 9.8 m/s²
Centripetal acceleration, a = v²/r
But v = ωr
a = g = ω²r

Therefore, the rotational speed of the ring module have to be 0.92 rad/s
Note: I'm not sure what do you mean by "weight 0.05 kg/L". I assume it means the mass per unit of length, so it should be "0.05 kg/m".
Solution:
The fundamental frequency in a standing wave is given by

where L is the length of the string, T the tension and m its mass. If we plug the data of the problem into the equation, we find

The wavelength of the standing wave is instead twice the length of the string:

So the speed of the wave is

And the time the pulse takes to reach the shop is the distance covered divided by the speed: