Answer:
86.4 m horizontal from landing spot
Explanation:
Find out how long before the ball hits the ground
vertical speed of ball = -2 m/s gravity = - 9.81 m/s^2
find time to hit ground from 100 m
( height will be<u> zero</u> when it hits the ground)
<u>0 </u>= 100 - 2 t - 1/2 ( 9.81) t^2
use Quadratic Formula to find t = 4.32 seconds
horizontal speed of ball = 20 m/s
in 4.32 seconds it will travel horizontally 20 m/s * 4.32 s = 86.4 m
Answer:
4
Explanation:
We know that intensity I = P/A where P = power and A = area through which the power passes through.
Now, let the initial intensity of the speaker be I₀ and its initial power be P₀. Since the intensity is increased by a factor of 4, the new intensity be I and new power be P.
So, I = P/A and I₀ = P₀/A
Now, if I = 4I₀,
P/A = 4P₀/A
P = 4P₀
Now, energy E = Pt, where t = time. So, P = E/t and P₀ = E₀/t
Substituting P and P₀ into the equation, we have
P = 4P₀
E/t = 4E₀/t
E = 4E₀
Since the energy is four times the initial energy, the energy output increases by a factor of 4.
Answer:
39.7 m
Explanation:
First, we conside only the last second of fall of the body. We can apply the following suvat equation:
where, taking downward as positive direction:
s = 23 m is the displacement of the body
t = 1 s is the time interval considered
is the acceleration
u is the velocity of the body at the beginning of that second
Solving for u, we find:
Now we can call this velocity that we found v,
v = 18 m/s
And we can now consider the first part of the fall, where we can apply the following suvat equation:
where
v = 18 m/s
u = 0 (the body falls from rest)
s' is the displacement of the body before the last second
Solving for s',
Therefore, the total heigth of the building is the sum of s and s':
h = s + s' = 23 m + 16.7 m = 39.7 m
B is the right answer. Multiply numbers you get the answer
