The speed of sound depends on the medium in which it is transported.
Sound travels fastest through solids, slower through liquids and slowest through gases.
So it will travel slowest through water at 55 degrees
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Complete Question
In an action movie, the villain is rescued from the ocean by grabbing onto the ladder hanging from a helicopter. He is so intent on gripping the ladder that he lets go of his briefcase of counterfeit money when he is 130 m above the water. If the briefcase hits the water 6.0 s later, what was the speed at which the helicopter was ascending?
Answer:
The speed of the helicopter is 
Explanation:
From the question we are told that
The height at which he let go of the brief case is h = 130 m
The time taken before the the brief case hits the water is t = 6 s
Generally the initial speed of the briefcase (Which also the speed of the helicopter )before the man let go of it is mathematically evaluated using kinematic equation as
Here s is the distance covered by the bag at sea level which is zero
=>
=> 
=> 
Answer:
The correct answer is 231 Mpa i.e option a.
Explanation:
using the equation of torsion we Have

where,
= shear stress at a distance 'r' from the center
T = is the applied torque
= polar moment of inertia of the section
r = radial distance from the center
Thus we can see that if a point is located at center i.e r = 0 there will be no shearing stresses at the center due to torque.
We know that in case of a circular section the maximum shearing stresses due to a shear force occurs at the center and equals

Applying values we get

<h2>
Mass of object in Earth is 1.37 kg</h2>
Explanation:
On planet B where the magnitude of the free-fall acceleration is 1.91g , the object weighs 25.74 N.
We have
Weight = Mass x Acceleration due to gravity
On planet B
25.74 = Mass x 1.91 g
25.74 = Mass x 1.91 x 9.81
Mass = 1.37 kg
Mass is constant for an object. It will not change with location.
Mass of object in Earth = Mass of object in Planet B
Mass of object in Earth = 1.37 kg
D is the answer
I hope it helps!