In a competition, weightlifter 1 lifts a 100 kg weight from the floor. Weightlifter 2
also lifts a 100 kg weight to the same height above the floor, but takes a longer time
to do so. Which of the following statements describes the work done and the power
used by the weightlifters?

Answer:

h=4+85*time - 1/2 32*time^2

16time^2-85*time-106=0

use the quadratic formula to solve for time (notice two solutions, one going up, one going back down).

time=(85+-sqrt(85^2+4*16*106) )/32

Explanation:

Recheck my work just in case I'm not good at this type of class but I wanted to help.

a. At maximum height h, the baseball has zero vertical velocity, so that with initial velocity v we have

[tex]0^2-v^2 = -2gh \implies h = \dfrac{v^2}{2g}[/tex]

Given that [tex]v = 30 \frac{\rm m}{\rm s}[/tex], the ball reaches a height of

[tex]h = \dfrac{\left(30\frac{\rm m}{\rm s}\right)^2}{2g} \approx \boxed{46\,\mathrm m}[/tex]

b. At max height, the baseball's vertical velocity is such that

[tex]0=v-gt[/tex]

For [tex]v = 30 \frac{\rm m}{\rm s}[/tex], we find

[tex]gt=30\dfrac{\rm m}{\rm s} \implies t = \dfrac{30\frac{\rm m}{\rm s}}g \implies t \approx 3.1 s[/tex]

which is half the time it spends in the air, making the total time about 6.1 s.

c. We saw in part (a) that

[tex]h = \dfrac{v^2}{2g}[/tex]

If we halve the initial speed and replace [tex]v[/tex] with [tex]\frac v2[/tex], we get

[tex]h = \dfrac{\left(\frac v2\right)^2}{2g} = \dfrac14 \cdot \dfrac{v^2}{2g}[/tex]

which means the max height is reduced by a factor of 1/4.

In part (b), we found the time to max height is

[tex]t = \dfrac{v}{g}[/tex]

and halving the initial speed gives

[tex]t = \dfrac{\frac v2}g = \dfrac12 \cdot \dfrac{v}{g}[/tex]

That is, the time to max height is reduced by a factor of 2 when the speed is halved, and so the overall time in the air is reduced by a factor of 2.

Answer:

If the charge on an electron be 1.6X10^-19 C, find the approximate number of electrons in 1 C. ANSWER: - As it is given that   1.6 X 10-19charge is of 1 electron, So 1 C charge is of = 1/1.6X10-19electron Now number of electrons = 1019/1.6 = (100 X 1018) / 16

We have that heat flow out of the copper sample  is mathematically given as

Q=8.86809J

Question Parameters

Endothermic Reaction

It is common knowledge that an endothermic reaction is one where the system absorbs heat energy from the environs.

Exothermic Reaction

An exothermic reaction is one where the system releases heat energy to the environs.

Generally the equation for Heat   is mathematically given as

[tex]Q=mCdt\\\\Therefore\\\\Q=0.349*0.385*(87-21)[/tex]

Q=8.86809J

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The distance the ball would have traveled is 1,066.72 m.

The relative velocity of two objects moving in the same or opposite direction can be used to determined the time of motion when the two objects move to a certain distance.

[tex](V_a + V_b) t = d\\\\(3 + 3 ) t =400\\\\t = \frac{400}{6} \\\\t = 66.67 \ s[/tex]

[tex]d = Vt\\\\d = 16\ m/s \ \ \times \ \ 66.67 \ s\\\\d = 1,066.72 \ m[/tex]

Thus, the distance the ball would have traveled is 1,066.72 m.

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The different ways the student is using energy in this picture is by using electricity to operate his tool and another energy is light energy.

Energy is the capacity to perform a job in physics. It could exist in many diverse variations, such as potential, kinetic, heat, electrical, chemical, nuclear, etc. In addition, energy is transmitted from one item to another through the processes of heat and work. After being transferred, energy is always primarily determined by its original nature. Therefore, heat transmission may seem like latent heat while the effort done may produce mechanical energy

All forms of energy have the quality of motion. A body, for instance, has kinetic energy while it is moving. A tensioned object, such as a spring or bow, has the ability to move even while at rest because of the way it is constructed; this design stores potential energy.

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Answer:

C Or D

Explanation:

The Child Should Get Checked On Before You Call The Police Thought,

Answer:

4.8 watts

Explanation:

power = voltage * current = 12.0 * 0.40 = 4.8 watts

Kinematics  can be explained as science that is used in describing the motion of objects, and these description can be made by the use of;

Kinematics which is a mechanics helps to develop sophisticated mental models which helps in serve describing motion of real-world objects.

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Answer: Hope this helps!!!!

Explanation:

it's true because we'll engery and causes of matter work together I think

We have that the Force  is mathematically given as

F=170.833N

Question Parameters:

Generally the equation for the Force   is mathematically given as

[tex]F=\frac{T}{d}[/tex]

Therefore

F=41/0.24

F=170.833N

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We have that the statements found falsifiable is

Henry Ford invented the first automobile.

Option A

Generally in as much Ford motor is a great vehicle company

He did not create the first automobile

Credit is give to Karl Benz for The first auto-mobile

Therefore

The statements found falsifiable is

Henry Ford invented the first automobile.

Option A

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Answer:

4km/h

Explanation:

her work is 2km away and she walks for a half hour to get there.

2km in 1/2 hour.

2=1/2x

multiply both sides by 2 to get rid of the fraction and you have your answer of 4km/h.

Answer:

True

Explanation:

In direct current (DC), the electric charge (current) only flows in one direction

So this true

Statement:

Jane does 5 joules of work when she closes her bedroom window. She applies a force of 6 newtons to do the job.

To find out:

The displacement of the window when she pulled it.

Solution:

Answer:

She pulls the window by 0.83 m.

Hope you could understand.

If you have any query, feel free to ask.

Answer:

The change in kinetic energy is twice the change in momentum

Explanation:

The momentum of an object is given by:

where

m is the mass of the object

v is its velocity

While the kinetic energy is given by

We want to check how these two quantities change when the speed of the object doubles, therefore when the new velocity is

For the momentum, we have

So, the momentum doubles.

For the kinetic energy, we have

So, the kinetic energy quadruples.

Therefore, the change in kinetic energy is twice the change in momentum.

Answer:

D. is the correct answer.

Explanation:

We can use sin cos tan method to solve Mx:

[tex]\frac{Mx}{5}=cos(37)[/tex]

[tex]Mx= cos(37) * 5[/tex]

[tex]Mx = 4[/tex]

So Mx should be 4 and head to right. as its positive.

We can use sin cos tan method to solve My:

[tex]\frac{My}{5} = sin(37)[/tex]

[tex]My = sin(37) * 5[/tex]

[tex]My = 3[/tex]

So My should be 3 and head to upwards. as its positive.

Final conclusion: D. is the correct answer.

a. Between the time the ball is first dropped and the first time it hits the ground, the ball's vertical velocity v at time t is given by

v = -gt

and its height y is

y = 2.00 m - 1/2 gt²

Solve the second equation for time t when the height is y = 0 (corresponding to the moment the ball first hits the ground) :

0 = 2.00 m - 1/2 gt²

1/2 gt² = 2.00 m

gt² = 4.00 m

t² ≈ 0.408163 s²

t ≈ 0.638877 s ≈ 0.639 s

Solve for v in the first equation at time this t :

v = -gt

v ≈ -6.26099 m/s ≈ -6.26 m/s

(That is, the ball hits the ground with a downward velocity of 6.26 m/s.)

b. The ball loses some energy after hitting the ground, and when it bounces back up, so it does so with a smaller upward initial velocity v' ("v prime").

At its maximum height h, the ball has zero vertical velocity. It's in freefall, so acceleration is constant. Then

0² - (v')² = -2gh

Solve for v' using the fact that h = 1.10 m after the first bounce:

(v')² = 2g (1.10 m)

(v')² = 21.56 m²/s²

v' ≈ 4.64327 m/s ≈ 4.64 m/s

We have that the Velocities is mathematically given as

a)v=2.8e5m/s

b)v_2=3.11e5m/s

From the question we are told

Generally the equation for the workdone   is mathematically given as

a)

[tex]-qEr=0.5m(u/2)^2\\\\Therefore\\\\1.6e-19*19*2.9e-3=0.5*9.1e-31*v^2/4[/tex]

v=2.8e5m/s

b)

applying work

[tex]-qEr=0.5m(u/2)^2\\\\1.6e-19*19*2.9e-3=0.5*9.1e-31(v_2^2-7.75e10)[/tex]

v_2=3.11e5m/s

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Answer:

Gas Giants don't have hard surfaces and instead have swirling gases above a solid core. like Jupiter and Saturn and are manly filled with helium and/or hydrogen.

Explanation:

Answer:

A. 13 cm

Explanation:

here the total diameter is given 4 cm,

here the radius then will be 2 cm.

use the formula of circumference of circle = 2πr ........where r is the radius

using the formula: 2 * π * 2 = 4π = 12.57 = 13 cm.

The angular acceleration of the object can be obtained from the solution as  432 cm^2/sec from the mean position.

We know that the simple harmonic motion is the kind of motion that the acceleration of the motion is such that the motion is directed towards the center of the motion. The implication of this is that the motion of the object would always tend towards the center of the motion of the object.

Then we would have to apply the formula that involves the angular velocity and the distance that is covered and thus we have to write the formula as follows;

α =  ω^2y

α = acceleration

ω = angular velocity

y = distance covered

Then we have;

α =  (12)^2 * 3

= 432 cm^2/sec

Thus the acceleration directed to the center is  432 cm^2/sec.

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Answer:

color gas?

Explanation:

i think

According to Ptolemy's model, he, too, believed in a geocentric Universe and that the planets and stars were perfect spheres, though Earth itself was not.

He further thought that the movements of the planets and stars must be circular since they were perfect and, if the motions were circular, then they could go on forever.

Shooting stars are very different from comets, although the two can be related. A Comet is a ball of ice and dirt, orbiting the Sun (usually millions of miles from Earth). ... A shooting star on the other hand, is a grain of dust or rock (see where this is going) that burns up as it enters the Earth's atmosphere.

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Answer:

Approximately [tex]50.5\; {\rm g}[/tex] (rounded to three significant figures.)

Explanation:

Let [tex]m_\text{p}[/tex] and [tex]m_\text{a}[/tex] denote the mass of the pineapple and the apple, respectively.

Let [tex]r_{\text{p}}[/tex] denote the distance between the pineapple and the pivot. Let [tex]r_{\text{a}}[/tex] denote the distance between the apple and the pivot.

Because of gravity, both the pineapple and the apple would exert a normal force on the seesaw. The magnitude of that force is equal to the weight of the fruit. Let [tex]g[/tex] denote the gravitational field strength.

Since these two forces are perpendicular to the seesaw, the magnitude of the torque exerted by the pineapple and the apple would be:

For the seesaw to maintain a rotational equilibrium, these two torques need to balance each other. Thus:

[tex]m_{\text{p}} \, g\, r_{\text{p}} = m_{\text{a}} \, g\, r_{\text{a}}[/tex].

Rewrite and simplify this equation to find an expression for the unknown mass of this apple, [tex]m_{\text{a}}[/tex]:

[tex]\begin{aligned}m_{\text{a}} &= \frac{m_{\text{p}}\, g\, r_\text{p}}{g\, r_\text{a}} \\ &= \frac{m_{\text{p}}\, r_{\text{p}}}{r_\text{a}}\end{aligned}[/tex].

Substitute in the values [tex]m_\text{p} = 121\; {\rm g}[/tex], [tex]r_\text{p} = 1.23\; {\rm m}[/tex], and [tex]r_{\text{a}} =2.95\; {\rm m}[/tex] and evaluate:

[tex]\begin{aligned}m_{\text{a}} &= \frac{m_{\text{p}}\, r_{\text{p}}}{r_\text{a}} \\ &= \frac{121\; {\rm g} \times 1.23\; {\rm m}}{2.95\; {\rm m}} \\ &\approx 50.5\; {\rm g}\end{aligned}[/tex].

Thus, the mass of the apple should be approximately [tex]50.5\; {\rm g}[/tex].