Explanation:
What is the weight of a 2.00-kilogram object on the surface of Earth?
2.00 N
4.91 N
9.81 N
19.6 N
Given parameters:
Mass of the object = 2kg
Unknown:
Weight of the object = ?
Solution:
The weight of an object is the force of gravity acting on the object;
Weight = mass x acceleration due to gravity
Acceleration due to gravity = 9.8m/s²
Now insert the parameters and solve;
Weight = 2 x 9.8 = 19.6N
A person weighing 785 Newtons on the surface of the Earth would weigh 47 Newtons on the surface of Pluto. What is the magnitude of the gravitational acceleration on the surface of Pluto?
1.7 m/s²
0.59 m/s²
0.29 m/s²
9.8 m/s²
Given parameters:
Weight on Earth = 785N
Weight on Pluto = 47N
Unknown:
Acceleration due to gravity on Pluto = ?
Solution
The mass of the body both on Earth and Pluto is the same.
Weight = mass x acceleration due to gravity
Now find the mass on Earth;
Acceleration due to gravity on Earth = 9.8m/s²
785 = mass x 9.8
mass = 
= 80.1kg
So;
Acceleration due to gravity on Pluto = 
Acceleration due to gravity = 
= 0.59m/s²
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.
