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
Answer:
Work done,W= 250J
Displacement , s = 60
We know that, Work done = Force x displacement
i.e , W = Fxs
250 J = F x 60m
F = 250/60
=4.16 N
Hence , 4.16 N of Force is applied on the body.
Answer:
Explanation:
From the equation of Newton's laws of motion
v = u + at where v is final velocity , u is initial velocity and t is time.
150 = 0 + a x 3
a = 50 m / s ²
s = ut + 1/2 at² ; s is distance travelled
s = 50 x 3 + .5 x 50 x 3²
= 150 + 225
= 375 m .
Answer:
I think c buti don't think I'm correct
Answer:
- <em>In both cases the tension in the rope is </em><u>equal to 500N</u>
Explanation:
It may be that in the case of the <em>tree</em>, the result is more intuitive, because you can think that there is only one force. But this is misleading.
To find the <em>tension in the rope</em>, you should draw a free body diagram. By doing so, you would find that the rope is static because there are two opposite forces. Assuming, for simplicity, that the rope is horizontal, a force of 500N is pulling to one direction (let's say to the right) and a force of 500N is pulling to the opposite direction (to the left). Else, the rope would not be static.
That analysys is the same for the<em> rope tied to the tree</em> ( the tree is pulling with 500N, such as the man, but in opposite direction) and when the rope is pulled by <em>two men</em> on opposite ends, each with<em> forces of 500N.</em>
Hence, the tension is the same and equal to 500N.
