Static electricity, caused by friction
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This question involves the concept of the conservation of energy.
(a) The child's speed halfway will be "12.13 m/s".
(b) The child's speed three-fourth way will be "14.86 m/s".
(a)
Using the <em>law of conservation of energy</em>:
Potential Energy Lost = Kinetic Energy Gained

where,
v = speed = ?
g = acceleration due to gravity = 9.81 m/s²
h = height lost = halfway = height/2 = 15 m/2 = 7.5 m
Therefore,

<u>v = 12.13 m/s</u>
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(b)
Using the <em>law of conservation of energy</em>:
Potential Energy Lost = Kinetic Energy Gained

where,
v = speed = ?
g = acceleration due to gravity = 9.81 m/s²
h = height lost = three-fourth way down = 
Therefore,

<u>v = 14.86 m/s</u>
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Learn more about the <em>law of conservation</em> of energy here:
brainly.com/question/20971995?referrer=searchResults
The attached picture shows the <em>law of conservation of energy</em>.
The Mass of the barter and the ball is 3.1kg
Data Given;
- F = 1.1*10^-9N
- r = 0.76m
- G = 6.67*10^-11 m^3 kg^-1 s^-1
Assuming the barter and the ball have equal mass, we can apply gravitational force formula.
<h3>Gravitational Force</h3>

This is product of the mass of the two bodies and divided by the square of their distance apart.
Substituting the values into the formula

From the calculations above, the mass of the barter and the ball is 3.1kg
Learn more on gravitational force here;
brainly.com/question/11359658
Yes indeed. Uh-huh, uh-huh. I would <span>choose to have
my genome sequenced to screen for diseases.
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D) activation gate - opens during depolarization