The primary purpose of a mirror is to ________

What kind of radiation is stopped by a piece of paper

Zina [86]

Three types of radioation - Alpha, Beta, Gamma. hope this helps

4 0

3 years ago

Read 2 more answers

?

Nana76 [90]

Answer:

Electron shell

Nucleus

Neutrons

Explanation:

An atom is made up of three fundamental subatomic particles which are the protons, neutrons and electrons.

Protons are the positively charged particles. Neutrons do not carry any charges.
Both protons and neutrons are found in the tiny nucleus at the center of that atom.
The electrons are negatively charged.
They are found outside the nucleus in electronic shells.

5 0

3 years ago

Championship swimmers take about 22 s and about 30 arm strokes to move through the water in a 50 m freestyle race.The swimmer's

Tasya [4]

Answer:

4400 Joules

73.33 Joules

25.9325 Joules

Explanation:

P = Power = 800 W

t = Time = 22 s

F = Force

r = Radius of arm = 90 cm

Energy

$E=P\times t\\\Rightarrow E=800\times 22\\\Rightarrow E=17600\ J$

As the efficiency is 25%

$E=0.25\times 17600\\\Rightarrow E=4400\ J$

Energy used in the race is 4400 Joules

Half of the energy is used in the arm

$E=\frac{4400}{2}=2200\ J$

So, per stroke of paddle

$E=\frac{2200}{30}=73.33\ J$

The energy expenditure per arm stroke is 73.33 Joules

Displacement will be the half of the perimeter of the circle

$s=\frac{1}{2}\times 2\pi r\\\Rightarrow s=\frac{1}{2}\times 2\pi 0.9\\\Rightarrow s=2.82743$

Work done

$W=F\times s\\\Rightarrow F=\frac{W}{s}\\\Rightarrow F=\frac{73.33}{2.82743}\\\Rightarrow W=25.9352\ J$

The average force of the hand on the water is 25.9325 Joules

3 0

3 years ago

What effect does friction have on a moving object? i forgot this pls help tyy

Vsevolod [243]

Answer:it causes the moving object to slow eventually stop

Explanation:

5 0

3 years ago

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

aksik [14]

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J