The oldest way ... the way we've been using as long as we've been
walking on the Earth ... has been to use plants. Plants sit out in the
sun all day, capturing its energy and using it to make chemical compounds.
Then we come along, cut the plants down, and eat them. Our bodies
rip the chemical compounds apart and suck the solar energy out of them,
and then we use the energy to walk around, sing, and play video games.
Another way to capture the sun's energy is to build a dam across a creek
or a river, so that the water can't flow past it. You see, it was the sun's
energy that evaporated the water from the ocean and lifted it high into
the sky, giving it a lot of potential energy. The rain falls on high ground,
up in the mountains, so the water still has most of that potential energy
as it drizzles down the river to the ocean. If we catch it on its way, we
can use some of that potential energy to turn wheels, grind our grain,
turn our hydroelectric turbines to get electrical energy ... all kinds of jobs.
A modern, recent new way to capture some of the sun's energy is to use
photovoltaic cells. Those are the flat blue things that you see on roofs
everywhere. When the sun shines on them, they convert some of its
energy into electrical energy. We use some of what they produce, and
we store the rest in giant batteries, to use when the sun is not there.
Answer:
The car traveled the distance before stopping is 90 m.
Explanation:
Given that,
Mass of automobile = 2000 kg
speed = 30 m/s
Braking force = 10000 N
For, The acceleration is
Using newton's formula
Where, f = force
m= mass
a = acceleration
Put the value of F and m into the formula
Negative sing shows the braking force.
It shows the direction of force is opposite of the motion.
For the distance,
Using third equation of motion
Where, v= final velocity
u = initial velocity
a = acceleration
s = stopping distance of car
Put the value in the equation
Hence, The car traveled the distance before stopping is 90 m.
Answer:
vpg = 0.064 N
Explanation:
Upthrust = Volume of fluid displaced
upthrust liquid on the cube g=10ms−2
vpg =0.2 x 0.2 x 0.2 x0.8 x 10= 0.064N
vpg = 0.064 N
hope it helps.
Answer:
0.000003782 m
0.000001891 m
0.000001197125 m
Explanation:
= Wavelength = 248 nm
D = Diameter of beam = 1 cm
f = Focal length = 0.625 cm
The angle is given by
The width is given by
The required width is 0.000003782 m
Minimum resolvable line separation is given by
The minimum resolvable line separation between adjacent lines is 0.000001891 m
when 
The new minimum resolvable line separation between adjacent lines is
