Average speed is the rate at which an object is moving at a given instant. True or False.

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

Explanation:

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

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.)

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]

Answer:

Im just here for the points man sorry

Explanation:

Answer:

Explanation:

v = ir

v/r = i

112/43 = i

2.60 ≈ i

Answer:

(a) The final velocity of the first proton after the collision = 8.3 m/s in the opposite to its initial direction

(b) The final velocity of the second proton after the collision = 7 m/s in the opposite to its initial direction

Explanation:

The given parameter of the protons are;

The velocity of the first proton, v₁ = 7.0 Mm/s

The velocity of the  second proton, v₂ = -8.3 Mm/s

The type of collision = Elastic collision

In an elastic collision, the kinetic and momentum energies are conserved, therefore, we have, for the initial and final momentums;

(m₁·v₁ + m₂·v₂)₁ = (m₁·v₁ + m₂·v₂)₂

1/2·(m₁·v₁² + m₂·v₂²)₁ = 1/2·(m₁·v₁² + m₂·v₂²)₂

Where, m₁ = m₂ or the protons, we get;

(v₁ + v₂)₁ = (v₁ + v₂)₂

(v₁² + v₂²)₁ = (v₁² + v₂²)₂

Therefore;

7.0 - 8.3 = v₁ + v₂

-1.3 = v₁ + v₂...(1)

7.0² + (-8.3)² = v₁² + v₂²

117.49 = v₁² + v₂²...(2)

From equation (1), we have;

v₁ = -1.3 - v₂

Plugging the value v₁ = -1.3 - v₂ in equation (2) gives;

117.49 = v₁² + v₂² = (-1.3 - v₂)² + v₂² = 2·v₂² + 12·v₂ + 1.69

∴ 2·v₂² + 2.6·v₂ + 1.69 - 117.49 = 0

2·v₂² + 2.6·v₂ - 115.8 = 0

Using the quadratic formula, we have;

v₂ = (-2.6 ± √(2.6² - 4×2×(-115.8)))/(2 × 2)

∴ v₂ ≈ -8.3 m/s or 7 m/s

When v₂ ≈ -8.3, v₁ = -1.3 - v₂ ≈ -1.3 - (-8.3) = 7

When v₂ ≈ 7, v₁ = -1.3 - v₂ ≈ -1.3 - (7) = -8.3

Therefore, the final velocity of the first proton after the collision = 8.3 m/s in the opposite to its initial direction

(b) The final velocity of the second proton after the collision = 7 m/s in the opposite to its initial direction.

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

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]

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]

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.

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

Answer:

True

Explanation:

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

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

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:

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].

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.

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 .

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

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

Answer:

c.an electron or positron

Answer:

your answer would be c

Explanation:

Answer:

13.78 mT

Explanation:

The peak voltage ε = ωNAB where ω = angular speed of coil = 1500 rpm = 1500 × 2π/60 rad/s = 50π rad/s = 157.08 rad/s, N = number of turns of coil = 250, A = area of coil = πr² where r = radius of coil = 10 cm = 0.10 m,

A = π(0.1 m)² = 0.03142 m² and B = magnetic field strength

So,

B = ε/ωNA  

substituting the values of the variables into the equation given that ε = 17 V

So, B = ε/ωNA

B = 17 V/(157.08 rad/s × 250 turns × 0.03142 m²)

B = 17 V/(1233.8634 rad-turns-m²/s)

B = 0.01378 T

B = 13.78 mT

Answer:

The responses to this question can be defined as follows:

Explanation:

During energy exchange E=hv, electrodes spring through one orbit to another

Please find the image file in the attachment.

Its absorption layer comprises 0.3 eV, 0.5 eV., 0.8 eV, 2.0 eV, 2.5 eV again, as light passes via material at low temperature those lines absorbed in the strata called absorption stratum.

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! ☺

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.

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.

Answer: True!

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

Answer:

0.06

Explanation:

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

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☺️☺️

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