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:
120°
Explanation:
Draw a free body diagram. There are three forces acting on the traffic light. Two tension forces acting along the cables, and weight.
The tension forces have an angle θ between them. That means each tension force forms an angle of θ/2 with respect to the vertical. So the y component of each tension force is:
Ty = T cos (θ/2)
Sum of the forces in the y direction:
∑F = ma
Ty + Ty − W = 0
2 Ty = W
Substituting:
2 T cos (θ/2) = W
If W = T, then:
2 W cos (θ/2) = W
2 cos (θ/2) = 1
cos (θ/2) = 1/2
θ/2 = 60°
θ = 120°
To solve this problem we will proceed to use the equations given for the calculation of the resistance, in order to find the radius of the cable. Once the length is found we can find the number of turns of the solenoid and finally the net length of it
The resistance of the wire is
= Resistivity
L = Length
A = Cross-sectional Area
That can be also expressed as,
Rearranging the equation for the length of the wire we have
The number of turns of the solenoid is
Denominator is equal to the circumference of the loop
Finally the Length of he solenoid is
Where \phi is the diameter of wire
Therefore the length of the solenoid is 7.532m