1. D
2. A
I’m not sure on 3
Centripetal force is given by F= mv²/r.
Given: m = 0.5 kg, v = 3 m/s, r = 0.5 m
Putting values,
F= mv²/r = 0.5× 3²/0.5 = 9 N
Forehead, Feet and Elbows, if the person is perfect health condition.
In order to decrease the friction on the slide,
we could try some of these:
-- Install a drippy pipe across the top that keeps continuously
dripping olive oil on the top end of the slide. The oil oozes
down the slide and keeps the whole slide greased.
-- Hire a man to spread a coat of butter on the whole slide,
every 30 minutes.
-- Spray the whole slide with soapy sudsy water, every 30 minutes.
-- Drill a million holes in the slide,and pump high-pressure air
through the holes. Make the slide like an air hockey table.
-- Keep the slide very cold, and keep spraying it with a fine mist
of water. The water freezes, and a thin coating of ice stays on
the slide.
-- Ask a local auto mechanic to please, every time he changes
the oil in somebody's car, to keep all the old oil, and once a week
to bring his old oil to the park, to spread on the slide. If it keeps
the inside of a hot car engine slippery, it should do a great job
keeping a simple park slide slippery.
-- Keep a thousand pairs of teflon pants near the bottom of the ladder
at the beginning of the slide. Anybody who wants to slide faster can
borrow a set of teflon pants, put them on before he uses the slide, and
return them when he's ready to go home from the park.
Answer:
a)
b)
Explanation:
a)
The width of the central bright in this diffraction pattern is given by:
when m is a natural number.
here:
- m is 1 (to find the central bright fringe)
- D is the distance from the slit to the screen
- a is the slit wide
- λ is the wavelength
So we have:
b)
Now, if we do m=2 we can find the distance to the second minima.

Now we need to subtract these distance, to get the width of the first bright fringe :
I hope it heps you!