Answer:
The rate of change of the shadow length of a person is 2.692 ft/s
Solution:
As per the question:
Height of a person, H = 20 ft
Height of a person, h = 7 ft
Rate = 5 ft/s
Now,
From Fig.1:
b = person's distance from the lamp post
a = shadow length
Also, from the similarity of the triangles, we can write:

Differentiating the above eqn w.r.t t:
Now, we know that:
Rate = 
Thus
<span>inclined plane formula is length/hight
so 5/2= 2.5
and work= f x d so
work= 5 x 104 x 10= 5200 W
</span>
Answer:
7. free fall -- h. 9.8m/s^2
3. Velocity -- x. 60 km/hr west
6. Acceleration -- d. change in velocity/time
8. Centrifugal -- s. towards the centre
13. Work done --w. Force * displacement
5. Uniform circular motion --j. spin cycle in washer
18. Power -- r. kW an hour
7. g -- a. 10N
hope this helps