1) A rock of mass 1.50kg is released from rest at a height of 30m. Ignore air resistance and
calculate;
(a) its speed half way down
(b) its speed on reaching the ground
(c) its total mechanical energy
(i) at a height of 30m
(ii) its kinetic energy half way through
(iii) its potential energy on striking the ground

Answers

Answer 1

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Related Questions

How much current is drawn by a television
with a resistance of 43 Ω that is connected
across a potential difference of 112 V?
Answer in units of A.

Answers

Answer:

Explanation:

v = ir

v/r = i

112/43 = i

2.60 ≈ i

A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal (thermal) energy of the gas?

Answers

Answer:

800J

Explanation:

Using the formula for change in the internal energy of a system

∆U = Q - W

Q = heat added to the system

W =workdone by system.

We know the process is an adiabatic one then, there no addition/ removal of heat, then Q= 0

(∆U = -W )

Then substitute for W, we have

∆U = -[-800]

∆U= 800J

∆U = 800J

The gravitational force between two objects is proportional to the square of the distance between the two objects.

a. True
b. False

Answers

Answer: True!

Explanation: The force is proportional to the square of the distance between 2 point masses

System A consists of a mass m attached to a spring with a force constant k; system B has a mass 2m attached to a spring with a force constant k; system C has a mass 3m attached to a spring with a force constant 6k; and system D has a mass m attached to a spring with a force constant 4k.
Rank these systems in order of increasing period of oscillation. (Use only the symbols < and =, for example A < B = C.)

Answers

Solution :

We know that the time period of oscillation of a spring mass system is given by :

[tex]$T = 2 \pi \sqrt{\frac{m}{k}}$[/tex]     , where m is mass and k is the spring constant

∴ [tex]$T_A = 2 \pi \sqrt{\frac{m}{k}}$[/tex]    .........(i)

  [tex]$T_B = 2 \pi \sqrt{\frac{2m}{k}}$[/tex] ..........(ii)

  [tex]$T_C = 2 \pi \sqrt{\frac{3m}{6k}} = 2 \pi \sqrt{\frac{m}{2k}}$[/tex]   ..........(iii)

  [tex]$T_D = 2 \pi \sqrt{\frac{m}{4k}}$[/tex]   ...............(iv)

Comparing the equations (i), (ii), (iii) and (iv)

We get

[tex]$T_B > T_A > T_C > T_D$[/tex]

So in increasing order of time period, we get

[tex]$T_D < T_C < T_A < T_B$[/tex]

Carla has a stick of butter. What can Carla do to the butter to show a chemical change?

Answers

Answer:

melting butter in a saucepan, as the butter cools it turns brown

Explanation:

although melting the butter is a physical change, but the butter being cooked and turning brown Is a chemical change, because due to the heat, its particles are being broken down, which is irreversible, and shows a chemical change.

what is the wavelength of a wave with the frequency of 330 Hz and a speed of 343 m/s

Answers

Answer:

The wavelength of a wave with the frequency of 330hz and a speed of 343m/s would be 1.04m

Explanation:

You can get the wavelength of a wave by dividing the speed of the wave by its frequency, which in this case would be:

343/300, which as a decimal number, it'd be 1.04.

I hope I helped you, and a "Brainliest" is always appreciated! ☺

Number 29 plz help physics

Answers

Answer:

a. E = 900000 J = 900 KJ

b. ΔT = 8.18 °C

c. Cost = $ 7.2  

Explanation:

a.

The energy can be given by:

[tex]E = Pt[/tex]

where,

E = Energy = ?

P = Power = 500 W

t = time = (0.5 h)(3600 s/1 h) = 1800 s

Therefore,

[tex]E = (500\ W)(1800\ s)[/tex]

E = 900000 J = 900 KJ

b.

The change in temperature of room air is given by the following formula:

[tex]0.5E = mC\Delta T\\[/tex]   (since 50% of energy is used to heat air)

where,

m = mass of air = 50 kg

C = specific heat of air = 1.1 KJ/kg.°C

ΔT = Change in temperature of air = ?

Therefore,

[tex](0.5)(900\ KJ) = (50\ kg)(1.1\ KJ/Kg.^oC)\Delta T[/tex]

ΔT = 8.18 °C

c.

First, we will calculate the total energy consumed:

[tex]E = (0.5\ KW)(6\ h/d)(30\ d)\\E = 90\ KWh[/tex]

Now, for the cost:

[tex]Cost = (Unit\ Cost)(Energy)\\Cost = (\$ 0.08\KWh)(90\ KWh)[/tex]

Cost = $ 7.2

If the motion of B is uniformly accelerated, at what time will both graphs have
exactly the same slope? Explain.

Answers

Answer:

Im just here for the points man sorry

Explanation:

Which theory states that the principle cause of forgetting is passage of time? A. motivated forgetting B. retrieval failure C. decay theory D. ineffective encoding

Answers

Decay theory

As time passes the information is less available for later retrieval, so that the information won’t be lost over time it is necessary to rehearse it.

mention & reasons why the ability to adapt to change is
important for improvement of your quality of life.

Answers

Answer:

The ability to adapt is important because :

1) It helps in the survival of human beings.

2) It brings more variation to the human kind.

3) It helps the species from getting endangered or extinct.

4) It brings transformation in the adapting kind.

Hope this helps you☺️☺️

Type the correct answer in each box. Round your answers to the nearest hundredth.

A ball with a mass of 1.5 kilograms is tied to the end of a rope. The ball is pulled to a height of 0.5 meters above the ground and released.
The ball has
joules of potential energy at position B. At position A, all of the energy changes to kinetic energy. The velocity of the ball at position A is
meters/second. Assume there’s no air resistance. Use g = 9.8 m/s2 , PE = m × g × h, and .

Answers

Hi there!

[tex]\large\boxed{PE = 7.35 J, \text{ }v \approx 3.13 m/s}[/tex]

To find the potential energy of the ball at B, we can use the equation:

PE = mgh

Plug the given gravity, mass, and height:

PE = (1.5)(0.5)(9.8) = 7.35 J

At A, all of this potential energy is changed to kinetic energy, so we can use the following equation:

v = √2KE/m

Plug in the solved for energy and mass:

v = √2(7.35)/1.5

Solve:

v ≈ 3.13 m/s

An object moves in a circle with a period of 0.025 hours. What is its frequency in Hz?

Answers

Frequency, , is defined as the rate of rotation, or the number of rotations in some unit of time. Angular frequency, , is the rotation rate measured in radians. These three quantities are related by f = 1 T = ω 2 π .

Frequency, is defined as the rate of rotation, or the number of rotations in some unit of time. Angular frequency, , is the rotation rate measured in radians. These three quantities are related by f = 1 T = ω 2 π .

what is frequency ?

The frequency is the number of oscillation per unit time and it is used for defining the cyclic process like rotation, oscillation, wave etc.

The SI unit of the frequency is denoted as Hertz and the symbol λ represents it where one hertz means the wave completed one cycle in one second.

The frequency which explains the phenomenon of oscillatory and vibration like the mechanical vibration, sound signals, light, frequency waves etc. The  “period” represented as the time required by the wave for one oscillation, i.e., it is inversely proportional to the frequency.

If the flashes, then the period is the time between the two flashes. And the frequency is the total number of flashes per second.

For more details regarding frequency, visit

brainly.com/question/14400059

#SPJ2

During the course of a demonstration the professor is called away. When he returns he finds a beaker of water that was at room temperature is now at a slightly higher temperature. There is a stirring rod on the desk and a cigarette lighter. The professor can assume that the temperature increase is due to either heat added or mechanical work done. mechanical work done on the system. heat added to the system.

Answers

Answer:

Either heat added or mechanical work done.

Explanation:

Since he found stirring rod on the desk and a cigarette lighter. This means that the beaker was probably either heated with the aid of fire from the lighter.

Also, the stirring rod could have been used to stir the water which will increase the kinetic energy which also means an increase in temperature.

Thus, it's either heat was added or mechanical work was done as a result of stirring.

un cubo de aluminio tiene un volumen de 45cm3 cuál es su masa en gramos

Answers

Material: aluminio volumen = v=64cm3 y masa = m

how to makee them love you I AM JK U ARE BEAUTIFUL U DONT NEED A MAN GIRL GO STUDY INSTEAD OF CHECKING UR PHONE 100 TIMES A DAY. ILYYY DONT FORGET THAT ​

Answers

Explanation:

lol ....you are right.......

Question 7 of 10
Which of these is a product of beta decay?
O A. An alpha particle
OB. A helium nucleus
C. An electron or a positron
O D. A beam of electromagnetic radiation

Answers

Answer:

c.an electron or positron

Answer:

your answer would be c

Explanation:

Mars can have bigger mountains than the Earth because it has a smaller mass and surface gravity.

True
False

Answers

Answer:

True

Explanation:

It’s True I think ........

What are three hazardous chemicals found in cigarette smoke?

Answers

Answer: I believe hydrogen cyanide, carbon monoxide, and ammonia are the three chemicals involved, but im not sure

a ball rolls horizontally of the edge of the cliff at 4 m/s, if the ball lands at a distance of 30 m from the base of the vertical cliff, what is the the hight of the cliff

Answers

Answer:

Approximately [tex]281.25\; \rm m[/tex]. (Assuming that the drag on this ball is negligible, and that [tex]g = 10\; \rm m \cdot s^{-2}[/tex].)

Explanation:

Assume that the drag (air friction) on this ball is negligible. Motion of this ball during the descent:

Horizontal: no acceleration, velocity is constant (at [tex]v(\text{horizontal})[/tex] is constant throughout the descent.)Vertical: constant downward acceleration at [tex]g = 10\; \rm m \cdot s^{-2}[/tex], starting at [tex]0\; \rm m \cdot s^{-1}[/tex].

The horizontal velocity of this ball is constant during the descent. The horizontal distance that the ball has travelled during the descent is also given: [tex]x(\text{horizontal}) = 30\; \rm m[/tex]. Combine these two quantities to find the duration of this descent:

[tex]\begin{aligned}t &= \frac{x(\text{horizontal})}{v(\text{horizontal})} \\ &= \frac{30\; \rm m}{4\; \rm m \cdot s^{-1}} = 7.5\; \rm s\end{aligned}[/tex].

In other words, the ball in this question start at a vertical velocity of [tex]u = 0\; \rm m \cdot s^{-1}[/tex], accelerated downwards at [tex]g = 10\; \rm m \cdot s^{-2}[/tex], and reached the ground after [tex]t = 7.5\; \rm s[/tex].

Apply the SUVAT equation [tex]\displaystyle x(\text{vertical}) = -\frac{1}{2}\, g \cdot t^{2} + v_0\cdot t[/tex] to find the vertical displacement of this ball.

[tex]\begin{aligned}& x(\text{vertical}) \\[0.5em] &= -\frac{1}{2}\, g \cdot t^{2} + v_0\cdot t\\[0.5em] &= - \frac{1}{2} \times 10\; \rm m \cdot s^{-2} \times (7.5\; \rm s)^{2} \\ & \quad \quad + 0\; \rm m \cdot s^{-1} \times 7.5\; s \\[0.5em] &= -281.25\; \rm m\end{aligned}[/tex].

In other words, the ball is [tex]281.25\; \rm m[/tex] below where it was before the descent (hence the negative sign in front of the number.) The height of this cliff would be [tex]281.25\; \rm m\![/tex].

51.Shoveling snow can be extremely taxing because the arms have such a low efficiency in this activity. Suppose a person shoveling a footpath metabolizes food at the rate of 800 W. (a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?

Answers

Complete question is;

Shoveling snow can be extremely taxing since the arms have such a low efficiency in this activity. Suppose a person shoveling a sidewalk metabolizes food at the rate of 800 W. (The efficiency of a person shoveling is 3%.)

(a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?

Answer:

A) P_out = 24 W

B) t = 1470 s

C) Q = 1140.72 KJ

Explanation:

We are given;

Input Power; P_in = 800 W

Efficiency; η = 3% = 0.03

A) Formula for efficiency is;

η = P_out/P_in

Making P_out the subject, we have;

P_out = η•P_in

P_out = 0.03 × 800

P_out = 24 W

B) We know that;

Power = work done/time taken

Thus;

P_out = mgh/t

We are given;

m = 3000 kg

h = 1.20 m

Thus, time is;

t = (3000 × 9.8 × 1.2)/24

t = 1470 s

C) amount of heat wasted is calculated from;

Q = (P_in - P_out)t

Q = (800 - 24) × 1470

Q = 1,140,720 J

Q = 1140.72 KJ

Which of the following is an example of a healthy behavior?
OA
Binge drinking of alcohol
OB.
Smoking cigarettes
OC.
Driving a car recklessly
OD.
None of the above

PE Not Physics

Answers

Answer moderate alcohol can be good for you health

Explanation: but I wouldn't do none of those things to be honest

SMARTEST

Answer:

none of the above

Explanation:

its an easy question haha

What is the difference between 1 celcius and 1 kelvin​

Answers

Answer:

One degree unit on the Celcius scale is equivalent to one degree unit on the kelvin scale. The only difference between these two scales is the zero point. The zero point on the Celcius scale was defined as the freezing point of water, which means that there are higher and lower temperatures around it.

A ball with a mass of 0.585 kg is initially at rest. It is struck by a second ball having a mass of 0.420 kg , initially moving with a velocity of 0.270 m/s toward the right along the x axis. After the collision, the 0.420 kg ball has a velocity of 0.220 m/s at an angle of 36.9 ∘ above the x axis in the first quadrant. Both balls move on a frictionless, horizontal surface.

Required:
a. What is the magnitude of the velocity of the 0.605kg ball after the collision?
b. What is the direction of the velocity of the 0.605kg ball after the collision?
c. What is the change in the total kinetic energy of the two balls as a result of the collision?

Answers

Answer:

a) [tex](v_1)=0.3989m/s[/tex]

b) [tex]\theta_1=80.5 \textdegree[/tex]

c) [tex]K.E=0.036J[/tex]

Explanation:

From the question we are told that:

Initial speed of 1st ball [tex]u_{1}=0 m/s[/tex]

Mass of 1st ball [tex]m_1=0.585kg[/tex]

Mass of 2nd ball [tex]m_2=0.420kg[/tex]

Initial speed of 2nd ball [tex]u_{2}=0.270 m/s[/tex]

Final speed of 2nd ball [tex]v_{2}=0.220 m/s[/tex]

Angle of collision [tex]\angle=36.9 \textdegree[/tex]

a)

Generally the equation for law of conservation is mathematically given by

[tex]m_1u_1+m_2u_2=m_1v_1^2+m_2v_2^2[/tex]

The final velocity [tex]v_1[/tex] is given as

[tex]0+(0.420)(0.270)=(0.585)(v_1)^2+(0.420)(0.220)^2[/tex]

[tex](v_1)^2=\frac{(0.420)(0.270)-(0.420)(0.220)^2}{0.585}[/tex]

[tex](v_1)^2=0.1591[/tex]

[tex](v_1)=0.3989m/s[/tex]

b)

Generally the equation for law of conservation is mathematically given by

[tex]m_1u_1+m_2u_2=m_1v_1cos\theta_1+m_2\theta_2[/tex]

[tex]0+(0.420)(0.270)=(0.585)(1.511)cos\theta_1+(0.420)(0.220)cos36 \textdegree[/tex]

[tex]cos\theta_1= \frac{(0.420)(0.270)-(0.420)(0.220)cos36 \textdegree}{(0.585)(0.3989)}[/tex]

[tex]cos\theta_1=0.1656[/tex]

[tex]\theta_1=80.5 \textdegree[/tex]

c)

Generally the equation for kinetic energy is mathematically given by

[tex]K.E=\frac{1}{2} mv^2[/tex]

1st Ball

[tex]K.E=\frac{1}{2} (0.585)(0.3989)^2[/tex]

[tex]K.E=0.0465J[/tex]

2nd ball

[tex]K.E=\frac{1}{2} (0.420)(0.220)^2[/tex]

[tex]K.E=0.101J[/tex]

Therefore the  change in the total kinetic energy of the two balls as a result of the collision is

[tex]0.101-0.0465[/tex]

[tex]K.E=0.036J[/tex]

On the Moon’s surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. What percent correction is needed to account for the delay in time due to the slowing of light in Earth’s atmosphere? Assume the distance to the Moon is precisely 3.84×108 m , and Earth’s atmosphere (which varies in density with altitude) is equivalent to a layer 30.0 km thick with a constant index of refraction n = 1.000293.

Answers

Answer:

[tex]T_d=2.8*10^-^6\%[/tex]

Explanation:

From the question we are told that

Distance b/w Earth and the moon [tex]d_e=3.84×10^8 m[/tex]

Thickness of Earth's atmosphere[tex]d_t=30km[/tex]

Constant index of refraction [tex]n = 1.000293.[/tex]

Generally the equation for percentage of time delay [tex]T_d[/tex] is mathematically given as

[tex]T_d=\frac{d(n-1)}{rm}*100\%[/tex]

[tex]T_d=\frac{(35*10^3)(1.000293-1)()100)}{3.674*10^8} *\%[/tex]

[tex]T_d=2.8*10^-^6 \%[/tex]

Therefore the general percentage correction needed because of tym deley is given as

[tex]T_d=2.8*10^-^6\%[/tex]

What is the wavelength associated with an electron with a velocity of 4.8x10*5 m/s?
(mass of the electron is 9.1 X 10-*31kg)

Answers

Answer:

Explanation:

Given the following data;

Mass = 9.1 X 10^{-31} kg

Velocity = 4.8x10⁵ m/s

Planck’s constant ( h ) = 6.6262 * 10^{-34}

To find the wavelength;

Applying de broglie's equation;

Wavelength = h/mv

Wavelength = ) = 6.6262 * 10^{-34}/(9.1 X 10^{-31} * 4.8x10⁵)

Wavelength = 1.52 * 10^{-71} meters

What voltage indicates the voltmeter connected to the ends of a conductor, if the ammeter connected in series with this conductor indicates a current of 400 mA. The resistance of the conductor is equal to 5kΩ.

Answers

Explanation:

V= Current × Resistance

V= 400mA × 5kohms

V= 2000V

Q1. Helmut rides 5km in 2h on his bike. His speed was *
a) 10km/h
b) 2.5km/h
c) 0.4km/h
d) 2.5km
Q2. A plane is travelling at 250km/h and must reach a target that is 3h 58min away. The distance to the target is. *
a) 1000km
b) 89500km
c) 62.5km
d) not enough information

Answers

Answer:

Speed of bike = 2.5 km/h

Distance travel = 1,000 km (Approx.)

Explanation:

Given:

Distance cover by Helmut = 5 km

Time taken = 2 hour

Find:

Speed of bike

Computation:

Speed = Distance / Time

Speed of bike = 5 / 2

Speed of bike = 2.5 km/h

Given:

Speed of plane = 250 km/h

time taken = 3 hr 58 min = 3.967 hr

Find:

Distance travel

Computation:

Distance = Speed x time

Distance travel = 250 x 3.967

Distance travel = 991.669

Distance travel = 1,000 km (Approx.)

Which of the following phenomena best demonstrates that light possesses wave characteristics?

A.The different colors of visible light
B.The transfer of electrons
C.The release of infrared light form radioactive materials
D.It shines and takes up space

Answers

The answer should be c

The release of infrared light from radioactive materials is what demonstrates light possessing wave characteristics.

What is a Wave?

This is defined as the propagation of disturbances from one place to another in an organized way.

The release of waves in a diffraction pattern is why option C was chosen as the most appropriate choice.

Read more about Wave here https://brainly.com/question/15663649

When the electrons reach the collector, they flow towards the positivly charged grid. The resulting current is measured. Note that as the electrons accelerate from the cathode toward the grid, they collide with the mercury atoms. Assume that these collisions are completely elastic. How does the collected current vary if the ΔVgrid is slowly increased? View Available Hint(s) When the electrons reach the collector, they flow towards the positivly charged grid. The resulting current is measured. Note that as the electrons accelerate from the cathode toward the grid, they collide with the mercury atoms. Assume that these collisions are completely elastic. How does the collected current vary if the is slowly increased? The current increases. The current remains constant. The current decreases.

Answers

Answer:

the current INCREASES.

Explanation:

In this experiment, the electrons are generated by a filament with very low speed, when they are subjected to a difference and potential ΔV they acquire the necessary speed to reach the regulation and the current can be measured.

Some electrons collide elastically with the atoms of the mercury gas that is much heavier and are scattered in any direction, so they do not reach the grid, by increasing the voltage this scattered electrons can acquire the necessary speed in the direction of grid to reach it and therefore are also measured, increasing the current.

Therefore, as the power difference increases, the current INCREASES.

3. Two spherical objects have masses of 4.7 x 105 kg and 7.9 x 103 kg. The
gravitational attraction between them is 68 N. How far apart are their
centers?

Answers

Answer:

0.06

Explanation:

Working on the problem at hand i calculated and got my answer to around simplified at 0.06

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