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3 years ago

Consider a ball thrown straight up in the air. At what position is its kinetic energy a maximum?

Physics

2 answers:

Lady_Fox [76]3 years ago

7 0

Answer:

The answer to your question is at the point where it is thrown.

Explanation:

Kinetic energy is the energy that possesses a body due to its motion. Its formula is

Ke = 1/2 mv²

Then, the kinetic energy is maximum when the velocity is the highest, and this is at the point where it is thrown, after this point, the velocity will be diminished and at the highest point will be equal to zero.

Aliun [14]3 years ago

6 0

Answer:

Explanation:

When a body is thrown upward, the body has it maximum velocity with the velocity of the throw and this velocity keep decreasing due to deceleration that is cause by acceleration due to gravity until it gets to the maximum height where the velocity is zero.

Since kinetic energy is determine by.

K.E = ½mv²

The mass of the body is constant all through.

Then, the maximum velocity is at the point of thrown, then the body has it maximum kinetic energy at the point of throw.

If we considered when it is landing too

It will have a maximum velocity at the point of throw again, where it lands on the hand.

The same kinetic energy will be recorded at the point of thrown and at the point it landed on his hands back.

This is why it has been recorded that, a straight bullet fired upward can kill someone at the point of return, because it will land at the same velocity it left the ground

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A 1.31 kg object is attached to a horizontal spring of force constant 2.70 N/cm and is started oscillating by pulling it 6.20 cm

goldfiish [28.3K]

Answer:

The answer is below

Explanation:

a) The change in energy is the difference between the final energy and the initial energy.

ΔE (energy change) = Ef (final energy) - Ei (initial energy)

$\Delta E=\frac{1}{2}kA_f^2 -\frac{1}{2}kA_i^2\\\\k=force\ constant=2.7\ N/cm=270\ N/m, A_f=final\ dispalacment= 3.7\ cm=0.037\ m,\\ A_i=initial \ displacement = 6.2\ cm=0.062\ m\\\\Hence:\\\\\Delta E=\frac{1}{2}(270)(0.037)^2 -\frac{1}{2}(270)(0.062)^2\\\\\Delta E=-0.334 \ J$

The negative sign shows that energy is lost to the environment. Hence 0.334 J is lost to the environment.

b) According to the law of conservation of energy, energy cannot be created or destroyed but transformed from one form to another.

The oscillating object loses energy due to wind resistance, friction between the spring and the object. Given that the air is frictionless, hence the energy loss is due to friction which is converted to heat.

6 0

3 years ago

Nerve impulses in a human body travel at a speed of about 100 m/s. Suppose a woman accidentally steps barefoot on a thumbtack. A

sasho [114]

T = 0.017 s

From the foot to the brain is almost the same as the height. We are not given the height of the woman, but to find "about" how much time, we need a height to work with.

She *could* be 1.7 m <- height = distance

Formula for speed, where k = speed, d = distance, t = time
k = d/t
Rearrange to solve for time:
t = d/k
Substitute known values:
t = (1.7 m) / (100 m/s)
Solve:
t = 0.017 s

Therefore, it takes about 0.017s for the impulse to travel from the foot to the brain.

6 0

3 years ago

A ship leaves a port at noon and travels due west at 20 knots. At 6 PM, a second ship leaves the same port and travels northwest

Amanda [17]

Answer:

$v = 12.44 Knots$

Explanation:

First ship starts at Noon with speed 20 Knots towards West

now we know that 2nd ship starts at 6 PM with speed 15 Knots towards North West

so after time "t" of 2nd ship motion the two ships positions are given as

$r_1 = 20(t + 6)\hat i$

$r_2 = 15(t)(cos45\hat i + sin45\hat j)$

now we can find the distance between two ships as

$x = \sqrt{(20(t + 6) - 10.6 t)^2 + (10.6t)^2}$

now we have

$x^2 = (120 + 9.4 t)^2 + (10.6 t)^2$

$x^2 = 200.72 t^2 + 14400 + 2256 t$

now we will differentiate it with respect to time

$2x\frac{dx}{dt} = 401.44 t + 2256$

here we know that

$t = \frac{90}{15} = 6 hours$

so we have

$x = 187.5$

now we have

$2(187.5) v = 401.44(6) + 2256$

$v = 12.44 Knots$

5 0

3 years ago

Why are lights in house wired in house wired in a parallel or nothing series

navik [9.2K]

Parallel circuits are mostly used in houses because if you turn one light off the rest stay on. While with a series circuit, if you turn one light off, all the lights turn off as well because they are all connected to one circuit (series). Parallel is usually 2 or more circuits which is why it lets you turn one thing off and everything stays on.

4 0

4 years ago

In gas chromatography, what are the advantages of (a) temperature programming? (check all that apply.)

TiliK225 [7]

The following statements apply:
1. Resolution of low boiling solutes is maintained.
2. Retention times of high boiling solutes are decreased.
Temperature programming refers to the process of increasing the temperature of gas chromatography column as a function of time. Temperature programming is usually applied to samples which contain a mixture of components whose boiling points are within narrow ranges

3 0

3 years ago