Squids propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracting the cavity
1 answer:
Answer:
v_squid = - 2,286 m / s
Explanation:
This exercise can be solved using conservation of the moment, the system is made up of the squid plus the water inside, therefore the force to expel the water is an internal force and the moment is conserved.
Initial moment. Before expelling the water
p₀ = 0
the squid is at rest
Final moment. After expelling the water
= M V_squid + m v_water
p₀ = p_{f}
0 = M V_squid + m v_water
c_squid = -m v_water / M
The mass of the squid without water is
M = 9 -2 = 7 kg
let's calculate
v_squid = 2 8/7
v_squid = - 2,286 m / s
The negative sign indicates that the squid is moving in the opposite direction of the water
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Answer:
8.1 N/49 N=0.1653 which means 16.53% of the weight of the object on Earth.
Explanation:
On the Moon, where the gravitational constant is 1.62 , the weight of the 5 kg object will be:
Where the answer is in Newtons (N) since all quantities are given in the SI system.
On Earth, on the other hand, the weight of the object is:
Therefore the object's weight on the Moon compared to that on Earth will be:
That is, 16.53% of the weight the object has on Earth.
A)
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:
Using (2) we can rewrite this as
And using (1), we find
Substituting into the last equation, we find the value of x:
B)
In this case, the kinetic energy is 1/10 of the total energy:
Since we have
we can write
And so we find: