If a new substance suddenly appears that wasn't there originally,
then a chemical change has occurred.
Like for example, (this is the only example I can think of right now):
-- You leave your bicycle outside in the rain, and it gets wet, and
a few days later there's some rust on it.
-- You scrape off some of the rust, take it to school, give it to the
Chemistry teacher, and ask her to analyze it and tell you what it
is. Later that day, she tells you it's a substance called "Iron oxide".
-- Where did that come from ? There was no iron oxide there.
There was only iron in the bicycle, and air, and water.
-- The iron oxide formed from a chemical change when the iron
on the surface of the bike combined with some of the oxygen in
the air, and molecules of a new substance were created. (For
some reason, the presence of water makes this chemical reaction
go faster.)
Answer:
the googles are 4.33mm from the edge
Explanation:
In this question, we are asked to calculate the distance of a set of googles from the edge of a pool.
We proceed as follows;
depth of pool , d = 3.1mm
Now, let i be the angle of incidence
i = arctan(1.8/1.2)
i = 56.31 degree
Using snell's law ,
n1 * sin(i) = n2 * sin(r)
1 * sin(56.3) = 1.33 * sin(r)
r = 38.72 degrees
Now,
distance of googles = 1.8+ d*tan(r)
distance of googles = 1.8+ 3.1 * tan(38.72)
distance of googles = 4.3 mm
Answer:
Explanation:
Given
Lawn mover running for 
and does 
We know Power is rate of work i.e.



Thus Power output is 
yeah it definitely 2 .:) :)
The kinetic energy of a moving object is given by

where m is the object's mass and v its velocity.
In our problem, the initial kinetic energy is:

while the final kinetic energy is:

So, the kinetic energy lost by Lucy and her bike is