21) A charged polyester ball is placed over a charged PVC pipe. The ball, which
has a mass of 1.2 grams, rests 42 cm above the pipe. If the ball and pipe have
the same negative charge, what is the charge on the ball?

Answer:

A and DDD

Explanation:

The two statements identify evidence that energy was conserved are, as the car rolls down the ramp, it speeds up because gravitational

potential energy is transformed into kinetic energy and as the car rolls across the floor, it stops because its kinetic energy is transformed into thermal energy due to friction, therefore the correct answer is option C.

Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.

As given in the problem statement a  toy car is released from rest at the top of a ramp. The car speeds up as it moves down the ramp. When it reaches the bottom of the ramp, the toy car rolls across the floor and

eventually stops.

Thus, it speeds up because gravitational potential energy is transformed into kinetic energy and as the car rolls across the floor, it stops because its kinetic energy is transformed into thermal energy due to friction, therefore the correct answer is option C.

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#SPJ5

Answer:

A sound mind in a sound body implies that you're capable of positive thinking for a better quality of life and physical functioning. When you exercise, your body releases endorphins, a chemical that triggers a positive response in the body. This shows that the more you sweat, the better you feel about yourself.

Explanation:

The distance above the ground the rock should be raised in order to hits the ground double of initial time is 4h.

The given parameters;

The time of motion of the rock from the given height is calculated as;

[tex]h = ut + \frac{1}{2} gt^2\\\\h = 0 + \frac{1}{2} gt_0^2\\\\h = \frac{1}{2} gt_0^2\\\\t_0^2 = \frac{2h}{g} \\\\t_0 = \sqrt{\frac{2h}{g} }[/tex]

When the time of motion is doubled to 2t₀, the height above the ground should be;

[tex]2(t_0) = 2(\sqrt{\frac{2h}{g} } )\\\\2(t_0) = \sqrt{\frac{4\times 2h}{g} }[/tex]

Thus, the distance above the ground the rock should be raised in order to hits the ground double of initial time is 4h.

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Answer:

Again, in accordance with Bernoulli's principle, the shape of the airflow facilitates the spread of laminar flow around it. The slower-moving currents beneath the airfoil exert greater pressure than the faster currents above it, giving lift to the aircraft.

Explanation:

Answer:          T = 93 N

Explanation:

Assuming the pulley is ideal meaning frictionless as mentioned and also negligible mass.

         ΣF = Σma

Mg - mg = Ma + ma

           a = g(M - m) / (M + m)

Now looking only at the larger mass as it falls

Mg - T = Ma

       T = Mg - Ma

       T = Mg - Mg(M - m) / (M + m)

       T = Mg(1  -(M - m) / (M + m))

       T = 16(9.8)(1 - (16 - 6.7) / (16 + 6.7))

       T = 93 N

or looking only at the smaller mass

T - mg = ma

T = m(g + a)

T = m(g +  g(M - m) / (M + m))

T = mg(1 +  (M - m) / (M + m))

T = 6.7(9.8)(1 +  (16 - 6.7) / (16 + 6.7))

T = 93 N

[tex]\\ \sf\longmapsto Pressure=\dfrac{Force}{Area}[/tex]

[tex]\\ \sf\longmapsto Pressure=\dfrac{10}{2.25}[/tex]

[tex]\\ \sf\longmapsto Pressure=4.4Pa[/tex]

Answer:

Area=1.5(1.5)=2.25m^2

Force of gravity=10N

\begin{gathered}\\ \sf\longmapsto Pressure=\dfrac{Force}{Area}\end{gathered}

⟼Pressure=

Area

Force

\begin{gathered}\\ \sf\longmapsto Pressure=\dfrac{10}{2.25}\end{gathered}

⟼Pressure=

2.25

10

\begin{gathered}\\ \sf\longmapsto Pressure=4.4Pa\end{gathered}

⟼Pressure=4.4Pa

The relationship between the length of the circle and its radius allows to find the result for the revolutions turned when the distance decreases  8.60m is:

           Angle = 17.8 rev

The length of a circle is given by the expression.

         L = 2π r

Where L is the length of the circle and r is the radius of the circle.

They indicate the radius of the drum is r = 7.71 cm = 7.71 10⁻² m, let's find the length of the circle.

         Lo = 2 π 7.71 10⁻²

         Lo = 0.4844 m

Let's find the angle that the drum has rotated, using a direct proportional rule. If rotate an angle of 2π radians when you descend 0.4844 m, what angle you rotate when you descend 8.60 m.

          #_ angles =  [tex]8.6 m \ \frac{2\pi \ rev} { 0.4844 m}[/tex]  

          #_angle = 111.55 radians

Let's reduce to revolutions.

         # _angles = 111.55 radians ( [tex]\frac{1 rev }{2\pi rad}[/tex] )

         #_angulo = 17.8 rev

In conclusion, using the relationship between the length of the circle and its radius, we can find the result for the revolutions turned when the distance decreases is:

           Angle = 17.8 rev

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Answer:

Explanation:

Earth's atmosphere contains greenhouse gases that trap heat. While they allow sunlight to pass through the atmosphere, they also prevent the heat it brings from leaving it.

Answer:

40m/s

Explanation:

50m/s - 10m/s = 40m/s

The pressure caused by water is: P = P0 + bgh = 1.013×10^5 + 10^3×9.81 × 1.5 = 1.18 atm

Answer:

Waves are most commonly caused by wind. Wind-driven waves, or surface waves, are created by the friction between wind and surface water. As wind blows across the surface of the ocean or a lake, the continual disturbance creates a wave crest.

Explanation:

Answer: Because

Running can significantly improve physical and mental health. As a form of aerobic exercise, running can reduce stress, improve heart health, and even help alleviate symptoms of depression. Some researchers think running may be so good for us because it's something we evolved to do. lol

Explanation:

Answer:

therefore, the correct answer is Option D.

Explanation:

a. 4×2=8kgm/s

b. 0.15×10=1.5kgm/s

c. 1.6×10³×0.5=800kgm/s

d. 2×950=1900kgm/s.

hope this helps you

Answer:

Explanation:

If we are to assume that the plane is at the bottom of a circular movement and just about to depart in level flight, then

(39.34 - 9.81) = 600²/R

R = 12,190.992211... m

Which is very close to the 1.2 km option

Answer: approximately 13-15 centimeters

Answer:

Explanation:

If we make a rather silly assumption that the runner does not leap upward somewhat as he leaves the edge of the first building, his initial vertical velocity is zero.

The time needed to drop 5 meters from vertical rest is

t = √(2s/g) = √(2(5)/9.8) = 1.01 s

so he needs a horizontal speed of at least

v = d/t = 8 / 1.01 = 7.91959...

v = 7.9 m/s. Better make it 8 m/s to be sure he clears the edge and lands on the roof.

Answer:

a Doe

A baby mouse is called a 'pinky', a male is called a 'buck' and a female is called a 'doe'.

(hope that helped)

Answer:

Explanation:

conservation of momentum

Initial momentum is zero

77v + 62(2.5) = 0

77v = -155

   v = -155/77 = -2.0129870...

 |v| = 2.0 m/s

Answer:

Below

Explanation:

c) To find the time of flight of a projectile (assuming from the given information that there is no vertical displacement) you can use this formula :

     t = 2(Vi) Sinx / g

     t = 2(51.5m/s) Sin(4) / 9.8 m/s^2

     t = 0.733 seconds

    t = 0.73 seconds

d) To find the displacement in the x-direction you can use this formula :

     dx = vi^2 sin(2x) / g

     dx = (51.5m/s)^2 sin(2(4)) / 9.8m/s^2

     dx = 37.6654 m  

     dx = 37.7 meters

e) To find the peak height of the projectile you can use this formula :

     v^2sin^2(x) = 2gh

     (51.5m/s)^2sin^2(4) = 2(9.8m/s^2)h

     h = 0.658 meters

     h = 0.66 meters

Hope this helps! Best of luck <3

Answer:

By Charles Law the volume of 1 cm^3 at standard conditions is

V = V0 * 273 / 293 = 1 cm^3 * .932 cm^3

Reducing the temperature to 0 deg C results in a volume of .932 cm^3

1 mole of gas contains 22.4 L of gas

1 L = 1000 cm^3

1000 cm^3 / L / (.932 cm^3 / container) = 1073   containers / L

So 1 mole of gas = 1073 containers * 22.4 L /container =  24,305 L

6.02E23 molecules / mole * 1 / 24305 molecules / mole = 2.48E19

number of molecules present = 2.48 * 10^19

(Easier to calculate volume of 1 cc

1 cc = 6.02E23 / (1000 * 22.4) = 2.69E19 molecules in 1 cc

Vol of 1cc = 273 / 293 = .932

2.69E19 * .932 = 2.51 * 10^19)

The particles can undergo small oscillations around x₂.

The given parameters;

The movement of the particles depends on the kinetic energy of the particles.

When kinetic energy of the particles is 100%, the particles can oscillate from x₁ to x₅.

However, when the total energy of this particles is reduced to one-third (¹/₃) or 33% of the initial energy of the particle, the oscillation of the particles will be reduced.

Since 33% is less than the half of the energy of the particle, the particle will oscillate between x₁ and x₂.

Thus, we can conclude that the particles can undergo small oscillations around x₂.

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The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m2, or kg·m−1·s−2).

Answer:

Only option 2 has the same number of oxygen and hydrogen atoms on each side of the arrow.

Explanation:

Answer:

C. When the waves overlap, they will cancel eanch other out and disappear

Explanation:

hope its help heart brainliest thnks

He developed his second law of motion by using a telescope to carefully follow and time the orbital motion of mars .

This is a device which is used to form magnified images of distant objects. Kepler used it to observe the orbit motion of mars.

He discovered that planets do not move with constant speed along their orbits which led to his second law of motion.

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A shopping cart that starts from rest, is accelerated for 4 s, moves at constant velocity for 4 s, and is decelerated for 4s until returning to rest, has an average acceleration of 0 m/s².

A shopper is pushing a cart down a grocery store aisle. The movement of the cart is:

All in all, at the initial time (t = 0 s), the velocity is 0 m/s (rest) and at the final time (t = 12 s) the velocity is 0 m/s as well (rest). The average acceleration in that period is:

[tex]a = \frac{v_{12}-v__o}{t_{12}-t_0} = \frac{0m/m-0m/s}{12s-0s} = 0 m/s^{2}[/tex]

A shopping cart that starts from rest, is accelerated for 4 s, moves at constant velocity for 4 s, and is decelerated for 4s until returning to rest, has an average acceleration of 0 m/s².

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Answer:0 m/s2

Explanation: Cus i said so.

Answer: distance travel after 5 seconds = 3×5 =15 m

so squirrel is away from me by distance of 15+ 5 = 20 m

Explanation:

Answer:

I believe 20 is the answer