We know that d=m/v where d is density, m is mass and v is volume. Lets transform formula to get v in times of d and m

Now we have to substitute our data to formula
V=

ml - its the answeer
Answer:
The answer to your question is:
a) t1 = 2.99 s ≈ 3 s
b) vf = 39.43 m/s
Explanation:
Data
vo = 10 m/s
h = 74 m
g = 9.81 m/s
t = ? time to reach the ground
vf = ? final speed
a) h = vot + (1/2)gt²
74 = 10t + (1/2)9.81t²
4.9t² + 10t -74 = 0 solve by using quadratic formula
t = (-b ± √ (b² -4ac) / 2a
t = (-10 ± √ (10² -4(4.9(-74) / 2(4.9)
t = (-10 ± √ 1550.4 ) / 9.81
t1 = (-10 + √ 1550.4 ) / 9.81 t2 = (-10 - √ 1550.4 ) / 9.81
t1 = (-10 ± 39.38 ) / 9.81 t2 = (-10 - 39.38) / 9.81
t1 = 2.99 s ≈ 3 s t2 = is negative then is wrong there are
no negative times.
b) Formula vf = vo + gt
vf = 10 + (9.81)(3)
vf = 10 + 29.43
vf = 39.43 m/s
Two copper spheres are currently 1.2 meters apart. One sphere has a charge of +2.2•10-4 C and the other has a charge of -8.9•10-4 C, then the the force between the charged spheres is the force attractive.
<h3>What is Coulomb's law?</h3>
Coulomb's law can be expressed as that the electrical force between two charged bodies is directly proportional to the product of the quantity of charge on the bodies and inversely proportional to the square of the separation distance between the two bodies.
As given in the problem two copper spheres are currently 1.2 meters apart.One sphere has a charge of +2.2•10-4 C and the other has a charge of - 8.9•10-4 C.
As per coulomb's law, opposite charges attract each other.
Thus, If one sphere has a charge of +2.2•10-4 C and the other has a charge of -8.9•10-4 C, then the the force between the charged spheres is the force attractive.
Learn more about Coulomb's law here ;
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The strong force is the only force that can overcome the repulsion between two <span>positively charged nuclei and bind them together.</span>
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Think about it like dog breeding. A "pure-bred" dog is like a pure substance, while a "mixed-breed" could be considered a mixture/