Answer:
Percentage change in tension is 3.8%
Explanation:
We have given initially frequency
= 440 Hz
Let tension in the string at this frequency is 
Now second frequency is 
Frequency in string is given by

From the relation we can say that


Percentage change in tension is equal to
%
So percentage change in tension is 3.8%
Answer:
I would say the answer is A... but I'm not so sure ....
It's true, when we lift an object we add energy to it.
because, when we lift an object by applying force , the object attains a height and hence the energy gets stored in it, in the form gravitational potential energy .
Answer:
c. hot material must be rising from the Sun's hotter interior
Explanation:
Granulation is the grainy appearance of the solar photosphere produced by the top of the convection cells in the sun.
The grainy appearance are produced by granules on the photosphere of the sun and granules are caused by convection currents of plasma within the sun's convection zone.
The interior of these granules are brighter (and thus hotter) than the exterior of the granules which are darker.
<u>So, the granulation pattern that astronomers have observed on the surface of the Sun tells us that hot material must be rising from the Sun's hotter interior.</u>
The correct answer is
<span>c. one person exerts more force than the other so that the forces are unbalanced.
In fact, the door is initially at rest. In order to move the door, a net force different from zero should be applied, according to Newton's second law:
</span>

<span>where the term on the left is the resultant of the forces acting on the door, m is the door mass and a its acceleration.
In order to move the door, the acceleration must be different from zero. But this means that the resultant of the forces acting on it must be different from zero: this is possible only if the forces applied by the two persons are unbalanced, i.e. one person exerts more force than the other.</span>