We are given that,

We need to find
when 
The equation that relates x and
can be written as,


Differentiating each side with respect to t, we get,



Replacing the value of the velocity


The value of
could be found if we know the length of the beam. With this value the equation can be approximated to the relationship between the sides of the triangle that is being formed in order to obtain the numerical value. If this relation is known for the value of x = 6ft, the mathematical relation is obtained. I will add a numerical example (although the answer would end in the previous point) If the length of the beam was 10, then we would have to



Search light is rotating at a rate of 0.96rad/s
Answer: Speed = 4 m/s
Explanation:
The parameters given are
Mass M = 60 kg
Height h = 0.8 m
Acceleration due to gravity g= 10 m/s2
Before the man jumps, he will be experiencing potential energy at the top of the table.
P.E = mgh
Substitute all the parameters into the formula
P.E = 60 × 9.8 × 0.8
P.E = 470.4 J
As he jumped from the table and hit the ground, the whole P.E will be converted to kinetic energy according to conservative of energy.
When hitting the ground,
K.E = P.E
Where K.E = 1/2mv^2
Substitute m and 470.4 into the formula
470.4 = 1/2 × 60 × V^2
V^2 = 470.4/30
V^2 = 15.68
V = square root (15.68)
V = 3.959 m/s
Therefore, the speed of the man when hitting the ground is approximately 4 m/s
It is 29 and a half days long
Speed = frequency * wavelength