Answer:
A
Explanation:
A circle graph typically represents numbers in percentages, used to visualize a part to whole relationship or a composition
<span>Wind power is produced from the
wind turbines or sails that uses air flow to convert it into mechanical power. It
is an alternative to fossil fuel burning, it is all around, renewable, clean,
produces no greenhouse gases and uses little land. The advantages of wind power
have been greatly praised by many. However, it has disadvantages. Wind power
especially at farm is noisy and may spoil the view for their neighboring people.
Also the amount of electricity depends on the strength of the wind. If no wind
is around, no electricity is produced. </span>
How many times did the original sample lose 50% of its radioactivity ?
-- Start with. . . . . . . . . . . . 12 grams.
-- Lose half of it once. . . . . . 6 grams left.
-- Lose half of it again . . . . . 3 grams left.
-- Lose half of it again . . . . . 1.5 grams left.
-- Lose half of it again . . . . . 0.75 gram left.
-- How many times did it lose half ? 4 times.
-- How long does it take to lose half ? 4.5 days.
(That's why it's called the 'half-life'.)
-- How long did it take to lose half, 4 times ?
(4 x 4.5 days) = 18 days .
Explanation:
If the satellite is moving too quickly then the gravitational attraction between the Earth and the satellite is too weak to keep it in orbit. If this is the case, the satellite will move off into space. This occurs at speeds around or above 11,200 metres per second (m/s).
- Mass of the diver (m) = 90 Kg.
- Height of the board from the ground (h) = 10 m.
- Acceleration due to gravity (g) = 9.8 m/s^2.
- Height of the diver from the ground when he reaches point C (x) = 5m
- Initial velocity (u) = 0 m/s
- We know, gravitational potential energy of a body = mass × acceleration due to gravity × height.
- Therefore, the gravitational potential energy of the diver when he reaches point C (GPE) = mg(h - x)
- or, GPE = [90 × 9.8 × (10-5)] J
- or, GPE = [90 × 9.8 × 5] J
- or, GPE = 4410 J
- For a freely falling body,
- v^2 - u^2 = 2gh
- or, v^2 = 2gh
- We know, kinetic energy of a body = 1/2 mv^2
- Therefore, kinetic energy of the diver when he reaches point C (KE) = 1/2 m(2gx)
- Here, 2gx = (2 × 9.8 × 5) = 98 (m/s)^2
- We have already seen v^2 = 2gh
- or, v = √2gh
- So, the velocity of the diver = √2gx = √98 m/s = 9.9 m/s
<u>Answers:</u>
<em><u>The </u></em><em><u>gravitational</u></em><em><u> potential</u></em><em><u> energy</u></em><em><u> of</u></em><em><u> the</u></em><em><u> </u></em><em><u>diver </u></em><em><u>when </u></em><em><u>he</u></em><em><u> reaches</u></em><em><u> point</u></em><em><u> C</u></em><em><u> </u></em><em><u>is </u></em><em><u>4</u></em><em><u>4</u></em><em><u>1</u></em><em><u>0</u></em><em><u> </u></em><em><u>J.</u></em>
<em><u>The </u></em><em><u>velocity</u></em><em><u> </u></em><em><u>of </u></em><em><u>the </u></em><em><u>diver </u></em><em><u>is </u></em><em><u>9</u></em><em><u>.</u></em><em><u>9</u></em><em><u> </u></em><em><u>m/</u></em><em><u>s.</u></em>
Hope you could get an idea from here.
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