Answer:
it would take 3.26 seg for the stone to fall to the water
Explanation:
If we ignore air friction then:
h=h₀ + v₀*t -1/2*g*t²
where
h= coordinates of the stone in the y axis ( height of the stone relative to the surface of the water )
h₀ = initial coordinates of the stone ( height of the cliff relative to the surface of the water = 52 m )
v₀ = initial <u>vertical </u>velocity = 0 ( since the ball is kicked horizontally , has only initial horizontal velocity , and has 0 vertical velocity )
t = time to reach a height h
g = gravity = 9.8 m/s²
since v₀ =0
h= h₀ - 1/2*g*t²
h₀ - h = 1/2*g*t²
t= √[2(h₀ - h)/g]
when the stone hits the ground h=0 ( height=0) , then replacing values
t=√[2(h₀ - h)/g]=√[2(52 m- 0 m )/(9.8m/s²)] = 3.26 seg
t= 3.26 seg
it would take 3.26 seg for the stone to fall to the water
Answer:
C. 1 and 2 are going up
Explanation:
The motor turns counterclockwise, so the pulley above it will also turn counterclockwise. This means the pulley to the right will turn counterclockwise. So block 2 will move up.
Since the belt is twisted on the left side, the pulley on the left will spin in the opposite direction (clockwise). So block 1 will also move up.
Answer:
The magnetic force is 0.3 N.
Explanation:
Given that,
Current in an unusual lightning strike, I = -400 A
The Earth’s magnetic field at that location is parallel to the ground and has a magnitude of 30 μT, 
We need to find the force exerted by the Earth’s magnetic field on the 25 m-long current.
The magnetic force is given by :
So, the magnetic force is 0.3 N.
There are actually two different kinds of mirrors, and the answer is different
for each one.
-- Plain old everyday hand mirror, vanity mirror, bathroom mirror, makeup
mirror, etc.
Opaque, reflecting silver coating is on the back of the glass.
Light from your tongue or your teeth flows to the front surface of the glass,
through the glass, out of the back surface of the glass, bounces off of the silver
coating on the back, reverses its direction, enters the back surface of the glass,
comes back through the glass again, leaves the front of the glass, goes into your
eyes, and you can see your teeth or your tongue.
Both surfaces of the glass, as well as the glass in between the surfaces, are
transparent. The silver coating on the back is opaque. I know that, because
when I look at the back of a mirror, I can't see any light coming through it.
The coating on the back is also reflective ... a big part of the reason why
a mirror works.
-- Expensive mirrors used by astronomers and eye-doctors.
Known as "first surface" mirrors.
Opaque, reflecting silver coating is on the <em>front</em> of the glass.
Light
from your tongue or your teeth flows toward the front surface of the glass,
but never actually gets there. It bounces off of
the silver coating on the front of
the glass, reverses its direction, goes into your eyes, and you can see your teeth
or
your tongue.
The glass is transparent, but that doesn't matter, because the light never reaches
the glass. It only goes as far as the opaque silver coating on the front, and is
reflected from there.
