Just before it strikes the ground, what is the watermelon's kinetic energy?

Explanation:

In this chapter, we will study the important concepts of kinetic energy and the

closely related concept of work and power.

A- Kinetic Energy

Kinetic energy is a physical quantity, which is associated with the moving objects

and defined as:

K = ½ mv2

If the body is stationary (v=0), its kinetic energy is zero. The SI unit of kinetic

energy is kg.m2

/s2

or Joule (J), where 1 J=1 kg.m2

/s2

. Kinetic energy is a scalar

quantity.

B- Work

The work is defined as the ability to perform a force along a certain displacement.

There are different types of work as follows:

1- Work done by a constant force

The work done by the constant force F is given by the scalar product of the force F

and the displacement d.

WF = F.d = Fd cosθ

where θ is the angle between the force and displacement. The above equation means

that the work is the product of the displacement magnitude by component of the

force parallel to the displacement. Therefore, work is a scalar quantity (only

magnitude, no direction) and can be positive, negative, or zero. The SI unit of work

is (N.m) or joule (J) where 1 N.m = 1 J.

Special cases and remarks:

• If the angle between the force and displacement is zero (parallel), the work is

WF = F d (maximum work)

Hi there!

We know that:

U (Gravitational Potential Energy) = mgh

Where:

g = acceleration due to gravity (m/s²)

m = mass (kg)

h = height/displacement (m)

Plug in the values:

U = 3 × 9.8 × 14 = 412 J

Answer:

A) 58 km

B) 30 mins

Explanation:

In pic details

graph in pic

A Torque is a twisting force, or turning moment, it is a vector quantity with both magnitude and direction e.g Turning the handle of a cork-screw clockwise and then counterclockwise will advance the screw first inward and then outward By convention, counterclockwise torques are positive and clockwise torques are negative.

The direction is perpendicular to both the radius from the axis and to the force. It is conventional to choose it in the right hand rule direction along the axis of rotation.

Counterclockwise is the positive rotation direction and clockwise is the negative direction.

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Answer/Explanation:

It False, because if You Round Both of them..

1.25= 1.30

1.04= 1.00

it's like, 1 dollar and 4 cents; compared to 1 dollar and 25 cents. Obviously 25 cents is a lot more than 4 cents.

Explanation:

The orbiting period of a satellite at a height h from earth' surface is

T=2πr32gR2

where r=R+h.

Then, T=2π(R+h)R(R+hg)−−−−−−−−√

Here, R=6400km,h=1600km=R/4

T=2πR+R4−−−−−−√R(R+R4g)−−−−−−−−−⎷=2π(1.25)32Rg−−√

Putting the given values,

T=2×3.14×(6.4×106m9.8ms−2)−−−−−−−−−−−−√(1.25)32=7092s=1.97h

Now, a satellite will appear stationary in the sky over a point on the earth's equator if its period of revolution around the earthh is equal to the period of revolution of the earth up around its own axis whichh is 24h. Let us find the height h of such a satellite above the earth's suface in terms of the earth,'s radius.

Let it be nR.Then

T=2π(R+nR)R(R+nRg)−−−−−−−−−−√

=2π(Rg)−−−−−√(1+n)32

=2×3.14(6.4×106m/s9.8m/s2)−−−−−−−−−−−−−−−⎷(1+n)32

(5075s)(1+n)32=(1.41h)(1+n)32

For T=24h, we have (24h)=(1.41h)(1+n)32

or (1+n)32=241.41=17

or 1+n(17)23=6.61

or n=5.61

The height of the geostationary satellite above the earth's surface is nR=5.61×6400km=6.59×104km.

Answer:

Cement, iron, and steel all work great!

Answer:

The distance traveled before takeoff is 1720 m

Explanation:

a = + 3.2 m/s²

t = 32.8 s

Vᵢ = 0 m/s

d = ?

Now,

d = Vᵢ × t + 0.5 × a × t²

d = (0 m/s) × (32.8 s) + 0.5 × (3.20 m/s²) × (32.8 s)²

d = 1720 m

Thus, The distance traveled before takeoff is 1720 m

-TheUnknownScientist 72

Answer:

not sure i need points

Explanation:

Answer: 20

Explanation:

Answer:

D

Explanation:

Process of elimnination + it's the only one that makes sense

An object will begin moving from rest when acted upon by forces that are greater in one direction than in any other direction. Hence, Option (D) is correct.

The definition of force in physics is: The push or pull on a massed object changes its velocity. An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude.

When  forces that are greater in one direction than in any other direction, resultant will be  unbalanced forces.  Unbalanced forces are those acting on a body when the net force acting on the body is greater than zero. The body alters its state of motion when unbalanced forces act on it.

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Answer:

Explanation:

Conservation of momentum

Let's say the first child was headed north

North momentum

75(0) + 20(2) + 15(3sin45) = (75 + 20 + 15)vn

vn = 0.6529 m/s

East momentum

75(0) + 20(0) + 15(3cos45) = (75 + 20 + 15)ve

ve = 0.28927 m/s

θ = arctan(0.28927/0.6529)

θ = 23.896...

θ = 24° east of north

The force of friction needed to overcome to move the box is 29.4N

According to Newton's second law;

[tex]\sum F_x = ma_x\\[/tex]

Taking the sum of force along the plane;

[tex]F_m -F_f = ma\\F_m -F_f = 0\\F_m=F_f = \mu R[/tex]

This shows that the moving force is equal to the frictional force

Given that

[tex]\mu = 0.6\\R = mg = 49N[/tex]

Get the frictional force;

Since

[tex]F_f = \mu R\\F_f = 0.6 \times 49\\F_f = 29.4N[/tex]

Hence the force of friction needed to overcome to move the box is 29.4N

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[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪  {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]

Acceleration due to gravity on that planet is half than that of om earth ~

that is ~

And it's weight is equal to ~

now, As we know ~

here ,

let find the mass of stone ~

Mass of the stone is 100 kg ~

I hope it helped

Explanation:

(a) A machine is a device by which we can either overcome a large resistive force at some point by applying a small force at a convenient point and in a desired direction or by which we can obtain a gain in the speed.

(b) An ideal machine is a machine whose parts are weightless and frictionless so that which there is no dissipation of energy in any manner. Its efficiency is 100%, i.e. the work output is equal to work input.

Answer:  You need to use Newton's law for the equation --->

Explanation: G  ×  M  ×  m / separation. Thats how youll get your answer !!

Addition of a proton to germanium  will convert it to arsenic (element 33) having different properties.

The atomic number of an atom is the number of protons in the nucleus of the atom. The atomic number serves as the identity of an atom. If the atomic number is changed by adding or removing protons, the identity of that atom changes.

Hence, when a proton is added to germanium, the  atom would become arsenic (element 33) and have different properties.

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Answer: Its B and D

I had the same question on usatestprep

11.4 m/s

Explanation:

The cord will break when the centripetal force exerted on it meets or exceeds the maximum tension [tex]T_{max}[/tex] that it can handle.

[tex]T_{max} = m\dfrac{v_{max}^2}{r}[/tex]

Solving for [tex]v_{max},[/tex] we get

[tex]v_{max}^2 = \dfrac{rT_{max}}{m}[/tex]

or

[tex]v_{max} = \sqrt{\dfrac{rT_{max}}{m}} =\sqrt{\dfrac{(1.3\:\text{m})(60\:\text{N})}{(0.6\:\text{kg})}}[/tex]

[tex]\:\:\:\:\:= 11.4\:\text{m/s}[/tex]

Explanation:

The initial kinetic energy [tex]KE_0[/tex] is

[tex]KE_0 = \frac{1}{2}mv_0^2 = \frac{1}{2}(400\:\text{kg})(10\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\;\:= 2×10^4\:\text{J} = 20\:\text{kJ}[/tex]

The final kinetic energy [tex]KE[/tex] is

[tex]KE = \frac{1}{2}mv^2 = \frac{1}{2}(400\:\text{kg})(30\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\:\:= 1.8×10^5\:\text{J} = 180\:\text{kJ}[/tex]

The work done W on the car is

[tex]W = \Delta{KE} = KE - KE_0[/tex]

[tex]\:\:\:\:\:\:\:= 180\:\text{kJ} - 20\:\text{kJ} = 1.6×10^5\:\text{J}[/tex]

The power expended P is

[tex]P = \dfrac{W}{t} = \dfrac{1.6×10^5\:\text{J}}{15\:\text{s}} = 10667\:\text{Watts}[/tex]

[tex]\:\:\:\:\:= 10.7\:\text{kW}[/tex]

Explanation:

Since the neutron is only moving at 1000 m/s, we are going to ignore the relativistic effects on its mass and energy. The mass of a neutron in [tex]m_n = 1.67×10^{-27}\:\text{kg}[/tex] so its kinetic energy KE is

[tex]KE = \frac{1}{2}m_nv^2[/tex]

[tex]\:\:\:\:\:\:\:\:= \frac{1}{2}(1.67×10^{-27}\:\text{kg})(10^3\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\:\:\:= 8.35×10^{-22}\:\text{J}[/tex]

A photon's energy E is defined as

[tex]E = h\nu[/tex]

where [tex]\nu[/tex] is the photon's frequency and h is the Planck's constant. Solving for the frequency, we get

[tex]\nu = \dfrac{E}{h} = \dfrac{8.35×10^{-22}\:\text{J}}{6.63×10^{-34}\:\text{J-s}}[/tex]

[tex]\:\:\:\:\: = 1.26×10^{12}\:\text{Hz}[/tex]

which is right around the infrared radiation range.

Answer:it’s C

Explanation:

by using graph of velocity vs. time for two objects, Item 4 and Item 5 statement makes an accurate comparison of the motions for objects. thus option C is correct.

velocity is the  rate of change of the position of the object with respect to  reference and it is complicated but velocity is basically speeding a particular object in a specific direction.

Velocity is a vector quantity which means both magnitude (speed) and direction are combinedly define define velocity. The SI unit of velocity is meter per second (ms-1) and the magnitude or the direction of velocity of a body changes leads to acceleration.

Speed and velocity are the two closest term but the major difference between speed and velocity is that speed gives us an idea that the object with the faster rate of movement r where as  velocity  speed up as well as  tells us the direction of the body

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Answer:

0.067 births per chipmunk per year

Explanation:

I took the test

Answer:

Explanation:

0.120 rev/s(2π rad/rev) = 0.24π rad/s

At the highest point of the arc, gravity must supply the required centripetal acceleration. As the normal force is 1/4 of his normal weight, then 3/4 of gravity acceleration must be used as centripetal acceleration

0.75g = ω²R

R = 0.75(9.81) / (0.24π)²

R = 12.942198...

R = 12.9 m

The radius of the circle is equal to 12.95m which is rotating with an angular velocity of 0.120 rev/s.

A body spins in a vertical circle so that its motion at different points is different from the motion of the body is said to be vertical circular motion.

The velocity and tension vary in maximum magnitude from the lowest to the highest position because of the effect of the gravitational force of the earth.

Given, the angular velocity of the Ferris wheel, ω = 0.120 rev/s

ω = 0.120 rev/s × 2π rad/rev

ω= 0.7536 rad/s

If r is the radius of the circle and 'm' is the mass of the jack.

From newton's second law of motion, the net force will be equal to

mg - N = mrω²

mg - (mg/4) = mrω²

r = 3g/4ω²

r = 3×9.81 / (4× 0.7536)

r = 12.95 m

Therefore, the radius of the circle in which the jack travels is equal to 12.95m.

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Your question is incomplete, most probably the complete question was,

Jack sits in the chair of a Ferris wheel that is rotating at a constant 0.120 rev/s. As Jack passes through the highest point of his circular part, the upward force that the chair exerts on him is equal to one-fourth of his weight. What is the radius of the circle in which Jack travels?

Answer:

d. The truck that left later was travelling faster

Explanation:

Both trucks travelled from the same place to the same place, meaning they both travelled the same distance;

They both arrive at the same time, but the second truck left later so it took less time to travel the distance than the first truck;

The only variable that can account for this difference is speed;

The one that left later, therefore, must have been going faster.

Answer:

Explanation:

s 0.12 + 1.20(1.80) = 2.28 m from the top.

Answer:

Explanation:

Normal force of the surface on the box will be

N = mg - Fsinθ

Ν = 10(9.8) - 600sin37

N = -263

As normal force cannot be less than zero, the applied force lifts the crate off the surface.

Now it's just a matter of finding the acceleration

In the horizontal direction, the acceleration is

a = F/m

a = (600cos37) / 10

a =  47.9181... m/s²

the crate weight is mg = 10(9.8) = 98 N.

In the vertical direction the acceleration is

a = ((600sin37 - 98) / 10)

a = 26.3089... m/s²

total acceleration is

a = √(47.9181² + 26.3089²)

a = 54.6653... m/s²

s = ½at²

t = √(2s/a)

t = √(2(1.0)/54.6653)

t = 0.19127...

t = 0.19 s

Answer:

negatively charged particle

valence electron  is a electron of an atom, located in the outermost shell (valence shell ) of the atom, that can be transferred to or shared with another atom.