Can power be negative in physics? I am doing a lab in which I run down the stairs as quickly as possible. They are 5.4m tall and my work is 5321.7 J. After calculating work, I got -5321.7 J. I am supposed to calculate my power used over 3 trials. The time for trial 1 was 4.69 and the seconds for trials 2 and 3 are 4.25. After calculating my power I got -1134.69 W and -1252.16 W. I am not sure if I got my power right. Is my power really negative or is my power positive?

Answer:

3000g for each side]

Explanation:

Answer:

I am so comfused

Explanation:

Type it into google

Answer:

Television,video game consoles

Answer:

A toaster

Explanation:

Since it heats up with heat waves of radiant energy

Answer:

he covered 80km his displacement was 20km

Explanation:

displacement is the distance from the starting point so in this case its 20 (50-30) and total distance covered is how many kilometers he drove in total

Answer:

Infrared photons carry lower radiation energy than the visible light.

Explanation:

       [tex]E = h*\nu (1)[/tex]

Infrared photons carry lower radiation energy than the visible light.

Visible light is the section of the spectrum of electromagnetic radiation which are visible to human eyes. The wavelength range of this light varies from 400 nm to 700 nm .

Each photon carries an energy that is directly proportional to its frequency, being this proportionality constant the Planck's constant h.

So, we can write the energy of a single photon as follows:

[tex]E=h\nu[/tex]      

Since there exists an inverse relationship between wavelength and frequency, and infrared radiation has longer wavelengths, this means that its frequency is lower than the one of the visible light.

So, an infrared photon carries less energy than one of the visible light.

To know more about Visible and infrared radiation, follow

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Split up the acceleration into horizontal and vertical components:

a = (1.4 m/s²) (cos(35º) i + sin(35º) j)

a ≈ (1.15 m/s²) i + (0.803 m/s²) j

Do the same with the pulling force (denoted by p):

p = (250 N) (cos(35º) i + sin(35º) j)

p ≈ (205 N) i + (143 N) j

By Newton's second law, the net horizontal force is proportional to the horizontal acceleration according to

∑ F = m a

The only horizontal force acting on the cart is the horizontal component of the pulling force. So we have

205 N = m (1.15 m/s²)

m ≈ 178.571 kg ≈ 180 kg

Answer: 22.1

Explanation:

Answer:

Acceleration

Explanation:

The quantity of the rate of change of velocity is termed the acceleration of the body.

Acceleration is the rate of change of velocity with time;

  A  = [tex]\frac{v - u}{t}[/tex]  

A is the acceleration

v is the final velocity

u is the initial velocity

t is the time taken

Answer:

b

Explanation:

Answer:

Steel is mostly composed of iron and carbon. It contains small amounts of manganese and even smaller amounts of silicon, phosphorous, oxygen, sulfur, and other elements.

...

Density of Steel.

carbon steel - 7.86

stainless steel - 7.9

Answer:

a) 3.162 m

b) 339.7 W

Explanation:

Assume ρ = 1.50*10^-6 Ωm, and

α = 4.000 10-4(°C)−1 for Nichrome

To solve this, we would use the formula

P = V² / R

So when we rearrange and make R subject of formula, we have

R = V² / P

Resistance of the heating coil, R

R = (110² / 500)

R = 12100 / 500

R = 24.2 ohms

Recall the formula for resistivity of a wire

R = ρ.L/A

Again, in rearranging and making L subject of formula, we have

L = R.A / ρ

To make it uniform, we convert our radius from mm to m.

Diameter, D = 0.5 mm

Radius of wire = 0.5 / 2 mm = 0.25 mm = 0.00025 m

We then use this radius to find our area

A = πr²

A = π * 0.00025²

A = 1.96*10^-7 m²

And finally, we solve for L

L = (24.2 * 1.96*10^-7 / 1.50*10^-6) =

L = 3.162 m

(b)

Temperature coefficient of resistance.

R₁₂₀₀ = R₂₀[1 + α(1200 - 20.0) ]

R₁₂₀₀ = R₂₀[1 + α(1180) ]

R₁₂₀₀ = 24.2[ 1 + 4.*10^-4 * 1180 ]

R₁₂₀₀ = 24.2[1 + 0.472]

R₁₂₀₀ = 24.2 * 1.472

R₁₂₀₀ = 35.62 ohms

Putting this value of R in the first formula from part a, we have

P = V² / R

P = (110² / 35.62)

P = 12100/ 35.62

P = 339.70 watts

(a) Length of the wire is 3.162 m

(b) Power delivered to the coil is 339.7 W

The electrical power is given by

P = V² / R

R = V² / P

Resistance of the heating coil, R

R = (110² / 500)

R = 12100 / 500

R = 24.2 Ω

Now the resistivity of a wire is given by

ρ= RA/L

here ρ = 1.50×10⁻⁶ Ωm

so after rearranging we get:

L = RA / ρ

Now, the radius of wire r = 0.5 / 2 mm = 0.25 mm = 2.5×10⁻⁴ m

So the cross sectional area can be calculated as follows

[tex]A = \pi r^2\\\\A = \pi \times (2.5\times10^{-4})^2\\\\A = 1.96\times10^{-7} m^2[/tex]

hence,

[tex]L = (24.2 \times1.96\times10^{-7} / 1.50\times10^{-6}) \\\\L = 3.162\; m[/tex]

(b)The dependency of resistance with temperature is as follows:

R = R₀[1 +  αΔT]

α = [tex]4\times10^{-4}^\;oC^{-1}[/tex] for Nichrome

[tex]R' = R [1 + \alpha (1200 - 20) ]\\\\R' = R[1 + \alpha (1180) ]\\\\R' = 24.2[ 1 + 4*10^{-4} * 1180 ]\\\\R' = 24.2[1 + 0.472]\\\\R' = 24.2 * 1.472\\\\R' = 35.62 \;\Omega[/tex]

So the power generated is :

P = V² / R

P = (110² / 35.62)

P = 12100/ 35.62

P = 339.70 watts

Learn more about electrical power:

https://brainly.com/question/26174188

Answer:

0.83W

Explanation:

Given parameters:

Voltage of the battery  = 10V

Resistance  =  120Ω

Unknown:

Power delivered by the resistor = ?

Solution:

The power delivered by the resistor can be derived using the expression below;

 Power = [tex]\frac{V^{2} }{R}[/tex]  

V is the voltage

R is the resistance

 Now, insert the parameters and solve

  Power  = [tex]\frac{10^{2} }{120}[/tex]   = 0.83W

Answer:

D. Gamma ray

Explanation:

You are welcome

Answer:

D) Gamma ray

Explanation:

Let me know if this is helpful.

Answer:

I'm not %100 sure but it might be d

Explanation:

Answer:

Explanation:

The kinetic energy (KE) of an object can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass

v is the velocity

From the question we have

[tex]k = \frac{1}{2} \times 200 \times {30}^{2} \\ = 100 \times 900[/tex]

We have the final answer as

Hope this helps you

Answer:

When it hits a wooden target, the ball exerts a force on the fibers in the wood, splintering. First, heavier objects that are moving have more kinetic energy than lighter ones: a In equation form: kinetic energy (joules) = 1/2 x mass (kg) x velocity2 (m/s)  Note that: 200 kg-m2/s2 = 200 (kg-m/s2) x m = 200 N x m = 200 joules.

Explanation:

Answer:

The correct option is (a).

Explanation:

Given that,

The energy of photon, E = 2.52 eV

We need to find the wavelength of the photon in nm. The formula for the energy of a photon is given by :

[tex]E=\dfrac{hc}{\lambda}\\\\\lambda=\dfrac{hc}{E}\\\\\lambda=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{2.52\times 1.6\times 10^{-19}}\\\\=4.93\times 10^{-7}\ m\\\\=493\ nm[/tex]

The nearest option is a) i.e. 492.34127 nm.

Answer:

According to Newton's third law, for every action force there is an equal (in size) and opposite (in direction) reaction force. ... The baseball forces the bat to the left; the bat forces the ball to the right. Together, these two forces exerted upon two different objects form the action-reaction force pair.

Answer:

#showerthoughts

Explanation:

Answer:

at least put the sentences in the Ques. smh

Explanation:

Answer:

B-The world’s largest pancake griddle is located in Penn Yan, NY, and measures 27 feet from end to end.

Explanation:

i got it right on my test

Answer:

A=1526N/m

B =40cm

Explanation:

Step one;

given

initial length=27cm= 0.27m

final length= 31.5cm= 0.315m

mass m= 7kg

Step two:

Required

A.

Force= mg

Force=weight= 7*9.81= 68.67N

extenstion e

e=31.5-27=4.5cm= 0.045m

K= spring constant

we know that F=ke

k=F/e

k=68.67/0.045

k=1526N/m

B.

New weight= 205N

F=ke

e=205/1526

e=0.13m

new length = 0.13+0.27= 0.4m

to cm=0.40*100=40cm

Answer:

C. 1400

Explanation:

The force exerted = f1 = 250

Diameter d1 = 0.02

r1 = d1/2 = 0.01

Diameter d2 = 0.15

r2 = d2/2 = 0.075

The mass of jack to lift

F1/A1 = f2/A2

250/r1² = f2/r2²

250/0.01² = f2/0.075²

When we cross multiply, we will have:

250x0.005625 = 0.0001f2

1.40625 = 0.0001f2

F2 = 1.40625/0.0001

F2 = 14062.5N

Force f = mg

g = 9.81

m = 14062.5/9.81

Mass = 1433Kg

Therefore option c is correct. A mass of 1400kg can be lifted by the jack

Answer: chemical property

Explanation:

Answer:

false. the medium never moves

Explanation:

Answer:

0.014

Explanation:

here

1.4 x 10^-2

=0.014

may this help

Answer:

107

Explanation:

Answer:

Q = 1386  J

Explanation:

Mass, m = 60 g = 0.06 kg

Specific heat of copper, c=385 J/kg K

It is heated from 20°C to 80°C.

We need to find the heat absorbed. It can be given by the formula as follows :

[tex]Q=mc\Delta T\\\\Q=0.06\times 385 \times (80-20)\\\\Q=1386\ J[/tex]

So, 1386  J of heat is absorbed.

Explanation:

avg velocity = total displacement / total time taken = (11 - (-9.8)) / 5.0 = 4.16m/s to the right when taken right to be positive

Answer:

4.Newton's second law of motion