A 6.5 kg rock thrown down from a 120m high cliff with initial velocity 18 m/s down. Calculate
the following using the energy/work formulae only:
1.The kinetic energy at the top of the cliff
2.The total mechanical energy at the top of the cliff
3.The kinetic energy of the Rock half way down 4.the speed of the Rock half way down
5.The speed of the Rock as it hits the ground​

Answer:

Yes

Explanation:

Answer:

Power = 2.5 [W]

Explanation:

To be able to solve this problem we must remember that power is defined as the relationship of the work done in a given time interval.

[tex]P=W/t[/tex]

where:

P = power [W] (units of watts)

W = work = 50 [J]

t = time = 20 [s]

Now replacing:

[tex]P=50/20\\P=2.5[W][/tex]

Answer:

2.5

Explanation:

Answer:

A

Explanation:

Answer:

The time taken by the projectile to hit the ground is 6.85 sec.

Explanation:

Given that,

Vertical height of cliff = 230 m

Distance = 300 m

Suppose, determine the time taken by the projectile to hit the ground.

We need to calculate the time

Using second equation of motion

[tex]s=ut+\dfrac{1}{2}gt^2[/tex]

Where, s = vertical height of cliff

u = initial vertical velocity

g = acceleration due to gravity

Put the value in the equation

[tex]230=0+\dfrac{1}{2}\times9.8\times t^2[/tex]

[tex]t=\sqrt{\dfrac{230\times2}{9.8}}[/tex]

[tex]t=6.85 sec[/tex]

Hence, The time taken by the projectile to hit the ground is 6.85 sec.

Answer:

energy level

s,p

electrons

Explanation:

I already done this trust me

In the notation 1 s² number 1 represents energy levels where electrons are located.The 4 parts on periodic table are s,p,d and f blocks.The 2 in 1 s² represents number of electrons in energy level.

Electrons present in an atom revolve in different orbits which are stationary states and are also called as energy levels. The energy levels are numbered as integers which are also called as principal quantum numbers.

Energy of the stationary state is given as E= -R

1/n² where R

is the Rydberg's constant. When an electron is excited, and it moves from lower to higher energy levels there is absorption of energy, while when it moves from higher energy level to lower energy level it radiates or gives out energy in the form of radiation.

They can also be defined as the distances between electron and nucleus of an atom . Electrons present in K energy level have least energy .Energy level diagrams are studied to understand nature of bonding , placement of electrons in orbits and and elemental behavior under certain conditions.

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Answer: it will take 1000 guitar players for sound intensity level to be 100 dB

Explanation:

Given that;

noise level of a single player = 70 dB

Intensity of one guitar will be;

SL= 10 × log(I/I₀)

where I₀ is hum threshold intensity = 10⁻¹² W/m²

I is intensity of sound produced by 1 guitar

SL is intensity level of one guitar

so we substitute

70 = 10 × log(I/10⁻¹²)

70/10 = log (I/10⁻¹²)

I = 10⁻¹² × 10⁷

I = 10⁻⁵ W/m²  

now Suppose n guitars produce sound intensity of 100 dB, then intensity of n guitars (In) will be;

100 = 10 × log(In/10⁻¹²)

log(In/10⁻¹²)  = 100/10

In = 10⁻¹² × 10¹⁰ =  10⁻² Wm²

we know that Now intensity of 1 guitar I = 10⁻⁵ W/m²

so Intensity of n guitars will be;

n × I = In

n = In / I

we substitute

n = 10⁻² Wm² /  10⁻⁵ W/m²

n = 1000

Therefore, it will take 1000 guitar players for sound intensity level to be 100 dB

Answer:

450m

Explanation:

[tex]s = ut + \frac{1}{2} a {t}^{2} \\ s = 0 + t + \frac{1}{2} a {t}^{2} \\ \frac{1}{2 } \times 9 \times {10}^{2} = 450m[/tex]

Answer:

they both are the mixture of substance

Answer:

a homogeneous mixture is a uniform mixture whose components appear to be in a single state while a heterogeneous mixture is non uniform mixture whose components remain separate

Explanation:

example of homogeneous_ water and ethanol

heterogeneous_ water and chalk

Answer:

v = 0.41 m/s

Explanation:

       [tex]\Delta K + \Delta U = W_{ffr} (1)[/tex]

       [tex]\Delta U = U_{f} - U_{o} = \frac{1}{2} * k * (x_{f} ^{2} - x_{0} ^{2} ) (3)[/tex]

       where k = force constant = 815 N/m

       xf = final displacement of the block = 0.01 m (taking as x=0 the position

      for the spring at equilibrium)

      x₀ = initial displacement of  the block = 0.03 m

       [tex]W_{ffr} = - \mu_{k}* F_{n} * \Delta x (4)[/tex]

       where μk = coefficient of kinettic friction, Fn = normal force, and Δx =

       horizontal displacement.

        [tex]\frac{1}{2} * m* v^{2} = W_{ffr} - \Delta U = W_{ffr} - (U_{f} -U_{o}) (6)[/tex]

        [tex]\frac{1}{2} * m* v^{2} = (- \mu_{k}* m*g* \Delta x) -\frac{1}{2} * k * (x_{f} ^{2} - x_{0} ^{2} ) (7)[/tex]

    [tex]\frac{1}{2} * 2.00 kg* v^{2} = (-0.4*2.00 kg*9.8m/s2*0.02m) +( (\frac{1}{2} *815 N/m)* (0.03m)^{2} - (0.01m)^{2}) = -0.1568 J + 0.326 J (8)[/tex]

Answer:

Astrophysicists study the physics of the universe. “Astrophysics” is a term that is often used interchangeably with “astronomy.” Atomic, molecular, and optical physicists study atoms, simple molecules, electrons, and light, as well as the interactions among them

Explanation:

Answer:

false

Explanation:

i just took the test <3

The period of a pendulum is not directly proportional to the mass of the bob. The period of pendulum is independent of the mass of the bob. Thus, the given statement is false.

A simple pendulum is the one which consists of a small metal ball called as the bob or a mass which is suspended from a fixed point by a long piece of thread such that the bob is free to swing back and forth from its mean position under the influence of the gravity.

The time period of a simple pendulum is the time taken by it to complete one oscillation. The formula for the time period or period (T) of a simple pendulum is T = 2π (√L/g), where L is the length of the pendulum thread and g is the acceleration due to gravity.

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Answer:

the red at the bottom should not count, but the red at the top is the least dense because it floats upon the other liquids

Explanation:

hope this helps

Answer:5,880

Explanation:Lol if I get this wrong sorry I’m trying to do this also but if you add the 1,764 joules and 4,116 joules in total if you add them all up it’ll give you 5,880 hope that helps.

Answer: a. (Q), (T), (E)

              b. (Q), (T), (E), (W)

Explanation: Thermal Energy and Temperature are closely related: when the temperature rises causing atoms or molecules to move, thermal energy is produced. Thermal energy is the energy within the system.

Mechanical Work is the amount of energy transferred due to an applied force.

Chemical Energy is the energy contained in the bonds of chemical structures of the molecules released when a chemical reaction happens.

Given the explanations, let's analyse the situations:

a. For an ice cube to be melting, it has to be absorbing heat, which means its thermal energy is changing and, consequently, so does its temperature;

b. First, the gas inside the cylinder reaches a thermal equilibrium, which means its thermal energy and temperature changed. Since there were  exchange of heat to reach the equilibrium, the gas absorbed or gave off heat. After the equilibrium, when the piston starts to be moved, the energy of the pressure is transferred to the gas, so mechanical work had been done.

1.

6090 J

2.

622 J

I bet so~

Answer:

Heat stroke

Explanation:

Heat Stroke is the most serious heat-related illness and requires immediate medical attention.

Answer:

Heat Stroke is the most serious heat-related illness and requires immediate medical attention. Symptoms include: confusion, fainting, seizures, very high body temperature and hot, dry skin or profuse sweating. CALL 911 if a coworker shows signs of heat stroke.

Explanation:

I HOPE THIS HELPS * pls mark me brainliest }

Answer:

d = 0.25 mm

Explanation:

The position that the Minimal fall in single silt diffraction pattern can be written as

y=λmD/d ..........eqn(1)

(y2 - y1 )= difference of y that exist between first and second minima

D= distance of slit from the screen=1.50m

d= width of the slit

λ= 633 nm = 633×10^-9m

y= position of pth minimal

eqn(1) can be written as

(y2 - y1)= λmD/d .........eqn(2)

If we substitute the given values we have

(y2 - y1 )= [ (2×633×10^-9 × 1.50) /d] -[ (1×633×10^-9 × 1.50) /d]

Simplyfying

(y2 - y1)=(9.495×10^-7)/d

But The distance between the first and second minima in the diffraction pattern = 3.75, which implies that (y2 - y1) = 3.75mm=

✓ we can substitute (y2 - y1)= 3.75mm=3.75 ×10^-3 into expression above

3.75 ×10^-3 =(9.495×10^-7)/d

The we can make "d" subject of the formula

d=(9.495×10^-7)/ (3.75 ×10^-3)

d=0.00025m

d=0.25×10^-3 m

d=0.25 mm

Hence, the width (in mm) of the slit is 0.25mm

Answer:

The specific charge is defined as a charge by mass ratio i.e e/m. The charge on an electron (e) = 1.602 X 10-19C. The mass of the electron (m) = 9.1×10−31Kg.

Answer:

I) True,  II) False,  III) False,  IV) True    

Explanation:

In this exercise, it is asked to answer different statements, for this we will use the relationship between angular and linear velocity

           v = w r

let's review the claims

I) True. From the initial equation we see that the linear velocity depends on the radius

II) False. All points rotate with the same angular velocity

III) False. Linear velocity changes with radius

IV) True. The angular velocity of all points is the same

At various radial points on a rotating Ferris wheel have, different linear velocity (True), different angular velocity (false), equal linear velocity (false) and equal angular velocity (True).

The angular velocity of a rotating Ferris is calculated as follows;

[tex]\omega = \frac{v}{r} = 2\pi N[/tex]

The linear velocity of a rotating Ferris is calculated as follows;

v = ωr

where;

The linear velocity increases with increase in radius.

Thus, we can conclude that, at various radial points on a rotating Ferris wheel have;

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Answer:

a = 0.009 J

b = 0.19 m/s

c = 0.005 J and 0.004 J

Explanation:

Given that

Mass of the object, m = 0.5 kg

Spring constant of the spring, k = 20 N/m

Amplitude of the motion, A = 3 cm = 0.03 m

Displacement of the system, x = 2 cm = 0.02 m

a

Total energy of the system, E =

E = 1/2 * k * A²

E = 1/2 * 20 * 0.03²

E = 10 * 0.0009

E = 0.009 J

b

E = 1/2 * k * A² = 1/2 * m * v(max)²

1/2 * m * v(max)² = 0.009

1/2 * 0.5 * v(max)² = 0.009

v(max)² = 0.009 * 2/0.5

v(max)² = 0.018 / 0.5

v(max)² = 0.036

v(max) = √0.036

v(max) = 0.19 m/s

c

V = ±√[(k/m) * (A² - x²)]

V = ±√[(20/0.5) * (0.03² - 0.02²)]

V = ±√(40 * 0.0005)

V = ±√0.02

V = ±0.141 m/s

Kinetic Energy, K = 1/2 * m * v²

K = 1/2 * 0.5 * 0.141²

K = 1/4 * 0.02

K = 0.005 J

Potential Energy, P = 1/2 * k * x²

P = 1/2 * 20 * 0.02²

P = 10 * 0.0004

P = 0.004 J

The total energy of the system is 0.009 J

The maximum speed of the object is 0.19 m/s

The kinetic and potential energies of the system when the displacement is 2.00 cm are 0.005 J and 0.004 J respectively

The object is under simple harmonic motion.

Given that the mass of the object m =0.5 kg , spring constant k = 20N/m

(a) The total energy of the system in SMH,

[tex]E=\frac{1}{2}kA^2[/tex]

If the amplitude of motion A = 3cm = 0.03m, then total energy

[tex]E=\frac{1}{2}*20*0.03*0.03 J\\\\E = 0.009J[/tex]

E = 0.009J is the total energy of the system.

(b) maximum speed of the object

the maximum kinetic energy of the object = total energy of the object

[tex]\frac{1}{2} m(v_{max})^{2} =E\\\\v_{max}=\sqrt{2E/m}\\\\v_{max}=\sqrt{2*0.009/0.5}\\\\v_{max}=0.19m/s[/tex]

0.19 m/s is the maximum speed

(c) KE and PE when x = 2cm = 0.02m

potential energy at x = 0.02

[tex]PE=\frac{1}{2}kx^2\\\\PE=\frac{1}{2}*20*0.02*0.02\\\\PE= 0.004J[/tex]

Now, Kinetic energy + potential energy = total energy

KE + PE = E

KE = E - PE

KE = 0.009J - ).004J

KE = 0.005J

The kinetic and potential energies are 0.005 J and 0.004 J respectively.

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Answer:

a) v = 32.8 m/s

b) v= 15.4 m/s

Explanation:

a)

        [tex]v = v_{o} + a*t (1)[/tex]

        where v₀ is the initial velocity and a is the acceleration, being t the

       time elapsed.

       [tex]v = 23.6 m/s + (1.30 m/s2 * 7.10 s) = 32. 8 m/s (2)[/tex]

b)  

       [tex]v = 23.6 m/s + ((-1.15 m/s2) * 7.10 s)) = 15. 4 m/s (3)[/tex]

Answer: F = 6262.2 kN

Explanation: Pressure is defined as force per area. But pressure varies according to the depth of a fluid: in air, it decreases the higher the altitude, while in water, it increases the deeper you go.

So, at the bottom of the tank, besides the pressure of air inside the tank and air outside the tank, there is pressure of water due to its depth.

Pressure due to the depth is calculated as

                                    [tex]P=h.\rho.g[/tex]

h is the depth in m

ρ is density of the fluid, in this case is water, so ρ = 997 kg/m³

g is acceleration due to gravity, which, in this case, is 3.71 m/s²

Then, pressure at the bottom of the tank due to variation in depth is

[tex]P=14.4(997)(3.71)[/tex]

P = 53263.73 Pa or 53.26 kPa

Assuming positive referential is downward, all pressures at the bottom point down, so total or resultant pressure is:

[tex]P_{r}=P_{1}+P_{2}+P_{3}[/tex]

[tex]P_{r}=150+88+53.26[/tex]

[tex]P_{r}=[/tex] 291.26 kPa

At last, pressure is force per area:

[tex]P=\frac{F}{A}[/tex]

[tex]F=P.A[/tex]

[tex]F_{r}=P_{r}.A[/tex]

[tex]F_{r}=291.26.10^{3}(2.15)[/tex]

[tex]F_{r}=[/tex] 626209 N or 626.2 kN

At the cylindrical tank's flat bottom, net force has magnitude 626.2 kN.

Answer:

Resistance of A is [tex]6\ \Omega[/tex] and B is [tex]3\ \Omega[/tex]

Explanation:

The voltage across both the resistances will be the same as they are connected in parallel.

V = Voltage = 6 V

[tex]I_B=2\ \text{A}[/tex]

Resistance is given by

[tex]R_B=\dfrac{V}{I_B}\\\Rightarrow R_B=\dfrac{6}{2}\\\Rightarrow R_B=3\ \Omega[/tex]

[tex]V_B=V_b-V_A\\\Rightarrow V_B=6-4\\\Rightarrow V_B=2\ \text{V}[/tex]

Series connection

[tex]V_A=4\ \text{V}[/tex]

The current is constant in series connection

[tex]I=\dfrac{V_B}{R_B}\\\Rightarrow I=\dfrac{2}{3}\ \text{A}[/tex]

[tex]R_A=\dfrac{V_A}{I}\\\Rightarrow R_A=\dfrac{4}{\dfrac{2}{3}}\\\Rightarrow R_A=6\ \Omega[/tex]

The resistance of A is [tex]6\ \Omega[/tex] and B is [tex]3\ \Omega[/tex].

Answer:

1: E

2: A

3: C

4: B

5: D

Explanation:

Answer: the answer is a

Explanation:

When it comes to phase shifts or phase change the greater the intermolecular interactions are the closer the molecules are to one another.

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