Work = force x distance (displacement) or the change in Kinetic energy
Carrying a box down a corridor has no external force acting on the box and therefore no work is being done.
Pushing against a locked door doesn't displace the door, so no work is being done.
Suspending a heavy weight with a strong chain requires, no force and actually prevents a force from acting on the chain.
Pulling a trailer up a hill on the other hand requires a person to apply a force to the trailer and displace it up the hill and therefore it requires work.
When you say "heavy", you're talking about the gravitational force
between that object and another object, so it depends on what the
"other object" is.
If the "other object" is, let's say, the sun, then the gravitational attraction
between the Earth and sun is about 80 times as much as the gravitational
attraction between the Moon and sun, because the Earth has about 80 times
the mass of the Moon.
But if, somehow, the weight you have in mind is the gravitational attraction
between the Earth and the Moon, then those forces are equal. The force
of gravity between two objects depends on the product of both masses,
and it's equal in both directions.
If that isn't clear to you, let me give you this additional fact that's guaranteed
to knock you even further off-balance:
Your weight on the Earth is determined by the product of
(your mass) times (the Earth's mass).
The Earth's weight on you is determined by the product of
(your mass) times (the Earth's mass).
Your weight on Earth is the same as the Earth's weight on you.
Would you like to prove it ?
-- Turn the bathroom scale upside-down, so that the step-pad
is on the floor.
-- Then step on it, so that you're standing on the bottom, which
is facing up.
-- If you placed a little mirror on the floor, so that you can read
the numbers, which are facing down toward the floor, you'll
read your own weight, even though with the scale upside-down,
you're weighing the Earth on you.
Answer:
4283.64 m away
Explanation:
= Bulk modulus
= Density
Speed of sound in a material is given by
If the round trip takes 6 seconds then the one way trip wil take 3 seconds
Distance = Speed × Time
So, the other submarine is 4283.64 m away
Answer:
54.6°
Explanation:
From law of reflection i=r.
So, construct the reflected ray at 55.7°degrees from the normal and let it fall on the other mirror.
Now draw the second normal at the point of incidence and again measure the angle of incidence, and draw the angle of reflection.
If you consider triangle AOB, one angle is ∠AOB=90°
and ∠OAB is 54.6°
From angle sum property third angle ie ∠ABO=180°-90°-54.6°=35.4°
So, the second incident angle will be 54.6°
Hence, the second reflected angle will be 54.6 degrees.
First you need to find out how many kilometers it travels for 60 minutes:
15km*60minutes = 900 Kilometers
Then you divide the distance traveled in one hour by 12 :
900kilometers/12minutes = 75km/h or 47mph
