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:
Vf₂ = 2 Vf₁
It shows that final speed of Joe is twice the final speed of Jim.
Explanation:
First, we analyze the final speed of Jim by using first equation of motion:
Vf₁ = Vi + at
where,
Vf₁ = final speed of Jim
Vi = initial speed of Jim = 0 m/s
a = acceleration of Jim
t = time of acceleration for Jim
Therefore,
Vf₁ = at ---------------- equation (1)
Now, we see the final speed of Joe. For Joe the parameters will become:
Vf = Vf₂
Vi = 0 m/s
a = a
t = 2t
Therefore,
Vf₂ = 2at
using equation (1):
<u>Vf₂ = 2 Vf₁</u>
<u>It shows that final speed of Joe is twice the final speed of Jim.</u>
Answer:
v = 2.974
Explanation:
Perhaps the formula should be
v = √(2*g*d (sin(θ) - uk*cos(θ) ) This is a bit easier to read.
v = √(2* 9.80*0.725(0.707 - 0.12*0.707) ) Substitute values. Find 2*g*d
v = √14.21 * (0.707 - 0.0849) Figure out Sin(θ) - uk cos(θ)
v = √14.21 * (0.6222)
v = √8.8422 Take the square root of the value
v = 2.974
An electric force exists between the following:
-Two negative objects
-Two positive objects
-A negative object and a positive object
