Answer:
0.6375 m/s
Explanation:
Let x be the distance of the man from the building
from the figure attached
initially the value of x=12
Given:

where the negative sign depicts that the distance of the man from the building is decreasing.
Now, Let The length of the shadow be = y
we have to calculate
when x=4
from the similar triangles
we have,
or

Differentiating with respect to time 't' we get

or

Now for x = 4, and
we have,

or

<u>here, the negative sign depicts the decrease in length and in the question it is asked the decreasing rate thus, the answer is </u><u>0.6375m/s</u>
Answer:
a) total moment of inertia is 1359.05 kg m^2
b) angular acceleratio is 0.854rad/sec^2
Explanation:
Given data:
m1=6.9 kg
L=4.88 m
m2=34.5 kg
R=1.22 m
we klnow that moment of inertia for rod is given as
J1=(1/12) ×m×L^2

moment of inertia for sphere is given as
J1=(2/5) ×m×r^2

As object rotates around free end of rod then for sphere the axis around what it rotates is at a distance of d2=L+R
For rod distance is d1=0.5*L
By Steiner theorem
for the rod we get 

for the sphere we get 

And the total moment of inertia for the first case is

b) F=476 N
The torque for system is given as

where a is angle between Force and distance d
and where d represent distance from rotating axis.
In this case a = 90 degree

M=476*2.44 = 1161.44 Nm
The acceleration is calculated as

= 0.854 rad/sec^2
Answer:
work being done on an object.
Answer. A. A man pushes a couch across the room
diagram identifies an axle:
Answer: B. Z
simple machine described as a shaft at the center of a wheel:
Answer: D. Wheel and axle
Type of lever:
A. a catapult