Answer:
D. 550 Hz
Explanation:
Frequency for string is given by

where v is the speed of the wave, L = m is the length
Frequency is inversely proportional to the Length of the string

from above relation we can write

The newly shortened string has 4/5 the length of the full string .i,e

Hence option D is correct
Nswer
<span>Work done = Pressure * ΔV [ change in volume ] </span>
<span>If ΔV=0, then no work is done </span>
<span>Zero work thermodyanamic process is called ' isochoric process.' </span>
<span>For example if a gas heated in a rigid container: the pressure and temperature </span>
<span>of the gas will increase, but the volume will remain the same. </span>
<span>This is called an isochoric thermodynamic process. </span>
<span>It is actually possible to do work on a system without changing the </span>
<span>volume, as in the case of stirring a liquid</span>
Answer:
hart beats in 0.8s=1
heart beat in 1s= 1/0.8
70 years=2207520000s
heart beat in 70years(2207520000s)=1.25x2207520000
=2759400000times
Explanation:
We call "terminal velocity" the constant speed of a falling body
when it is no longer accelerating.
We know that if a body is not accelerating, then the net force
on it is zero.
From the question, we know that the downward force of gravity
on the skydiver is 800 N.
If the 800 N downward plus the air resistance upward add up
to zero, then the air resistance upward must also be 800 N.