Den pushes a desk 400 cm across the floor. He exerts a force of 10 N for 8 s to move the desk. What is his power output? (Power: P = W/t) 1.25 W 5 W 40 W 500 W

Answer:

A dark fringe

Answer:

The nail exerts an equal force on the hammer in the opposite direction.

Explanation:

The Newtons third law states that there is an equal an opposite reaction for every action. When hammer pushes the nail, the nail will push the hammer back in opposite direction. When the hammer hits a nail then nail will exert the equal and opposite force to the hammer. These both objects will exert force on each other in opposite directions.

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Answer:

Answers are

1. "The nail exerts an equal force on the hammer in the opposite direction."

2. "500 N"

3. "The iron piece exerts a force of 1 N on the magnet in the opposite direction."

4. "When mass moves closer to the point of rotation, rotational inertia decreases."

5. "The skater spins slower because his rotational inertia has increased."

Explanation:

Answer:

12 i. The work done by Wale = 107.910 kJ

The work done by Lekan = 117.720 kJ

Total work done = 225.36 kJ

ii. Wale's power =  4.3164 kW

Lekan's power = 3.924 kW

Wale has more power and is more powerful than Lekan

13. 313.92 N

Explanation:

i. The work done, W = Force, F × Distance moved by the force, D

The given parameters are

The mass of Wale = 55 kg

The mass of Lekan = 60 kg

The acceleration due to gravity, g =9.81 m/s²

The motion force of Wale and Lekan are;

Motion force of Wale = 9.81 × 55 = 539.55 N

Motion force of Lekan = 9.81 × 60 = 588.6 N

The work done by Wale = 539.55 × 200 = 107910 J = 107.910 kJ

The work done by Lekan= 588.6 × 200 = 117720 J = 117.720 kJ

107910 + 117720 =225630 J = 225.36 kJ

ii. Power = Work done/time

Wale finished the race in 25 s, therefore, his power = 107910/25 = 4316.4 W

Lekan finished the race in 30 s, therefore, his power = 117720/30 = 3924 W

Wale has more power and is more powerful than Lekan

13. The velocity ratio = 5

V. R. = Distance moved by effort/(Distance moved by load)

Efficiency = 80%

Work done by effort = x

Work done by machine = Efficiency × Work done by effort  = 0.8 × x

Distance moved by effort, E = V. R. × Distance moved by load, D = 5 × D

Work done by effort = Force × Distance moved = 200×9.81× E

Work done by effort = 1962×E = 1962×E = 1962×5×D

Work done by machine = 1962 × D, when D = 1, we have;

0.8 × 1962×1 = 1569.6 J

Work done by effort = Force × Distance moved

Work done by effort = Force × 5×D = Force × 5 (D = 1)

From the principle of conservation of energy, we have;

Energy is neither created nor destroyed

Therefore

Work done by effort = Force × 5 = 1569.6 J

Force = 1569.6 /5 = 313.92 N.

Answer:

O- to track how fast a heart beats

Explanation:

Answer:

B. A magnet being moved into or out of the coil

Explanation:

Faraday law of electromagnetic induction states that when there is change in flux , an emf is produced . Among the given instances , only in case of B , flux is changing . So current will be induced in the coil . We shall see how it takes place .

A wire carrying constant current will produce magnetic flux in nearby coil but there is no change in flux because current as well as position of wire with respect to coil are  not changing  .

Passing of magnetic field through a stationary coil produces flux in the coil but here too there is no change in flux so no current will be induced .

A magnet positioned near a coil creates magnetic flux in the coil but the magnitude of flux remains constant so no change in flux and no creation of induced current .

Answer:

=33 .3×10^6Ω

=33.3M Ω

Explanation:

We were told to calculate the Resistance value,

Given the heart pacemaker fires as 72 times a minute, which is the time constant

Then we can convert the pacemaker fires of 72 times a minute to seconds for unit consistency.

1 minutes= 60secs

Then ,Time constant τ=60secs/72=0.8333 seconds

Time constant τ can be calculated using the formula below

τ= RC

Where R= resistance

C = capacitance

Then making RESISTANCE subject of formula we have

R=τ/C

But Capacitance=25.0-nF = 25×10^25F

Substitute the values we have

R=0.833/25×10^25

=33 .3×10^6 Ω

But can still be converted to M Ω= 33.3M Ω

Therefore, the resistance is 33 .3×10^6 Ω or 33.3M Ω

NOTE: 1M= 10^6

The value of the resistance will be "3.33×10⁷ Ω".

According to the question,

Capacitor, C = 25.0 nF

60 sec - 72 fires

now,

Time for 1 fire,

[tex]t = \frac{60}{72}[/tex]

 [tex]= \frac{5}{6} \ sec[/tex]

Now,

⇒            [tex]V = V_0 (1-e^{-\frac{t}{RC} })[/tex]

     [tex]0.632 V_0=V_0(1-e^{\frac{-\frac{5}{6} }{R.25 n C} })[/tex]

[tex]e^{-\frac{1}{R\times 30\times 10^{-9}} } = 1-0.632 = 0.368[/tex]

                  [tex]= 2.72[/tex]

By taking "log" both sides,

⇒ [tex]ln \ e^{\frac{1}{R\times 30\times 10^{-9}} } = ln \ 2.72[/tex]

hence,

The Resistance be:

⇒ [tex]R = \frac{10^9}{30}[/tex]

       [tex]= 3.33\times 10^7 \ \Omega[/tex]

Thus the above approach is right.

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Answer:

5000 N/m².

Explanation:

The following data were obtained from the question:

Density (d) = 1000 kg/m³

Acceleration due to gravity (g) = 10 N/kg

Height (h) = 50 cm = 50/100 = 0.5 m

Pressure (P) =.?

Pressure is related to density and height by the following equation:

P = dgh

Where

P is the pressure.

d is the density.

g is the acceleration due to gravity.

h is the height.

With the above formula, we can obtain the pressure at the bottom of the cup as follow:

P = dgh

P = 1000 x 10 x 0.5

P = 5000 N/m²

Therefore, the pressure at bottom of the cup is 5000 N/m².

Answer:

585×10⁸ m

Explanation:

Distance = rate × time

d = (2.998×10⁸ m/s) (3.25 min) (60 s/min)

d = 585×10⁸ m

Answer:

The distance the car travels is 115500 m in S.I units

Explanation:

Distance d = vt where v = speed of the car and t = time taken to travel

Now v = 99 km/h. We now convert it to S.I units. So

v = 99 km/h = 99 × 1000 m/(1 × 3600 s)

v = 99000 m/3600 s

v = 27.5 m/s

The speed of the car is 27.5 m/s in S.I units

We now convert the time t = 70 minutes to seconds by multiplying it by 60.

So, t = 70 min = 70 × 60 s = 4200 s

The time taken to travel is 4200 s in S.I units

Now the distance, d = vt

d = 27.5 m/s × 4200 s

d = 115500 m

So, the distance the car travels is 115500 m in S.I units

Answer:

a) 4 m

b) 24 m/s

c) 0.174 kg

Explanation:

a) Tension in string equation

The information given are;

The wavelength is equal to the rope length , λ = L

The tension = 100 N

The displacement of a point on the rope is y(x, t) = (0.1 m) sinπ x sin 12πt

Given that the wavelength = the length of the rope, the rope is on second harmonic

L = 2·n and the length of the wire = 2 × 2 = 4 m given the dimensions are in meters

b) Where k = 2·π/λ

v = ω/k = 12π/(2·π/λ)= (12π/2π)×λ = 24 m/s

c) f = v/λ = 24/4 = 6 Hz

[tex]f = \dfrac{\sqrt{\dfrac{T}{m/L} } }{2L} = \dfrac{\sqrt{\dfrac{100}{m/4} } }{2 \times 4}[/tex]

[tex]6 \times 8= {\sqrt{\dfrac{100}{m/4} } }[/tex]

m/4 = 100/2304

m = 0.174 kg.

Answer:

0.25 m/s

Explanation:

Average velocity = change in displacement / change in time

v = (1.5 m − 2.5 m) / (6 s − 2 s)

v = -0.25 m/s

The average speed is 0.25 m/s.

Answer:

0.25 m/s

Explanation:

khan academy

Answer: Alicia and the president do not have enough of a particular resource. Alicia doesn’t have enough time, and the president doesn’t have enough money.

Explanation: This is Plato's sample answer.

Answer:

Option B. 2 A.

Explanation:

The following data were obtained from the question:

Resistance 1 (R1) = 1 Ω

Resistance 2 (R2) = 2 Ω

Resistance 3 (R3) = 3 Ω

Potential difference (V) = 12 V.

Current through the 3 Ω (I3) =?

Next, we shall determine the total resistance of the circuit.

This can be obtained as follow:

Resistance 1 (R1) = 1 Ω

Resistance 2 (R2) = 2 Ω

Resistance 3 (R3) = 3 Ω

Total resistance (R) =.?

R = R1 + R2 + R3

R = 1 + 2 + 3

R = 6 Ω

Next, we shall determine the current flowing in the circuit.

This can be obtained as follow:

From ohm's law,

Voltage (V) = current (I) x resistance (R)

V = IR

Potential difference (V) = 12 V.

Resistance (R) = 6 Ω

Current (I) =?

V = IR

12 = I x 6

Divide both side by 6

I = 12/6

I = 2 A.

Since the circuit is in series connection, therefore, the same current will flow through each resistor.

Therefore, the current through the the 3 Ω load is 2 A.

Explanation:

SI is the international system of units

It was developed to express magnitudes and quantities

Derived Quantities

Answer:

These are quantities calculated from two or more measurements

Explanation:

They can't me measured directly.

They can only be computed.

They are calculated in PHYSICAL SCIENCE.

hope it helps.

Answer:

The correct option is;

3. The total mechanical energy is constant as the block moves back and forth

Explanation:

The total mechanical energy is the sum of the potential and kinetic energies of the system

For a system that is isolated from the effects of external forces, but being acted upon by the internal conservative forces within the system, the total mechanical energy is constant

For a black and spring system, we have total mechanical energy, E = 1/2×K×A².

Where;

K = Constant

A = The amplitude of motion

Therefore, where there is no loss to friction, with A, remaining constant, the total mechanical energy will be constant.

Answer:

10 seconds

Explanation:

because the cat is moving one m/s slower than the dog, the dog has a relative speed of 1 m/s. 10 meters would take 10 seconds for the dog to cover

Answer:

c

Explanation:

The marginal cost curve image  has been attached from which we can clearly, indicate that

ATC = average total cost

AFC = average fixed cost

AVC = average variable cost.

From the graph we can indicate that the marginal cost curve

(c) Lies above the AVC curve when the AVC curve slopes downward.

Answer:

10N

Explanation:

Applying the Hooke law:

F = kx

F: Force

k: stiffness coefficient

x: stretched distance

F = 10N/m x 1m = 10N

Answer:

Diffusion depends among many other things also upon the concentration gradient of the diffusing substance.For example if there are two boxes with given particles first isolated from each other and if they are bought in contact, then there is a net diffusion of particles from a box with higher concentration of particles to box with lower concentration. And also diffusion rate depends at any instant directly on the concentration difference between them at that instant.Now the vaccum is equivalent to an empty box which means with this one leads to a maximum diffusion rate when bought in contact with a box with particles because there is maximum concentration difference.That is vaccum is empty ( except for energy perturbations and a small concentration of particles which will be zero for our purpose) and any bunch of particles will find least resistance to diffuse as just outside this bunch there is ‘0' concentration of the particles.

Answer:

v1 = −2.201946 m/s ( to the left)

v2 = 0.7780534 m/s ( to the right)

Explanation:

Given the following :

Mass of first glider (m1) = 0.149kg

Initial Speed of first glider (u1) = 0.710 m/s

Mass of second glider (m2) = 0.308kg

Initial Speed of second glider (u2) = 2.27m/s

For elastic collision:

m1u1 + mu2u2 = m1v1 + m2v2

Where V1 and v2 = final velocities if the body after collision.

Taking right as positive ; left as negative

u1 = 0.710m/s ; u2 = - 2.27m/s

u1 - u2 = - (v1 - v2)

0.710 - - 2.27 = - v1 + v2

v2 - v1 = 2.98 - - - - (1)

From:

m1u1 + mu2u2 = m1v1 + m2v2

(0.149 * 0.710) + ( 0.308 * - 2.27) = (0.149 * v1) + (0.308 * v2)

0.10579 + (-0.69916) = 0.149 v1 + 0.308v2

−0.59337 = 0.149 v1 + 0.308v2

Dividing both sides by 0.149

v1 + 2.067v2 = −0.59337 - - - - - (2)

From (1)

v2 = 2.98 + v1

v1 + 2.067(2.98 + v1) = −0.59337

v1 + 6.16 + 2.067v1 = −0.59337

3.067v1 = −0.59337 - 6.16

3.067v1 = −6.75337

v1 = −6.75337 / 3.067

v1 = −2.201946 m/s ( to the left)

From v2 = 2.98 + v1

v2 = 2.98 + (-2.201946)

v2 = 0.7780534 m/s ( to the right)

Answer:

answer= 73.1256 [tex]i[/tex]

Explanation:

The electric charge linear density is equal to 8.8 x[tex]10^{-9}[/tex]

the length of the string is 3.1m

The magnitude of the electric field at the length of the string equal to 5.2 meters can be calculated with the formula ;

- E = λ / 4πε₀ [ [tex]l[/tex]  / α ( α +

Solution:

E =  8.8 x[tex]10^{-9}[/tex] / 4πε₀ [ 3.1/ 5.2( 5.2 + 3.1) ] [tex]i[/tex]

= 1018.0995 [0.07183] [tex]i[/tex]

=  73.1256 [tex]i[/tex]

Answer:

B.

Explanation:

as there is a '-' sign before the magnification value, it forms a real image.

so the last two options get cancelled.

as the value of magnification is 0.87 ie. lesser than 1, we can say that the image is smaller.

The type of image is formed by a lens if m = -0.87 would be smaller than the object and the object is real

A lens is a transmissive optical tool that employs refraction to focus or disperse a light beam. The power of the lens is expressed in the dioptre which is the reciprocal of the focal length of the lens.

The image formation through the lens is calculated with the help of the lens formula given as follows

1/f = 1/v - 1/u

where f is the focal length of the lens

u is the distance of the object from the lens

v is the distance of the image formed from the

magnification (m) = size of image /size of the object

As given in the problem image is formed by a lens if m = -0.87

Thus, the negative sign represents that the image formed by the object is real, and the magnitude of the magnification is less than 1 this represents that size of the image is smaller than the size of the object.

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Answer:

5.3333 sec

Explanation:

initial speed: u = 108km/hr or 30 m/s

final speed: v = 0m/s

distance travelled: s = 80m

time the car took to stop: = t sec

[tex]v^{2} - u^{2}[/tex] = 2as,

a = ([tex]v^{2} - u^{2}[/tex])/2s

a = (0-900)/160

a = -5.625 [tex]ms^{-2}[/tex]

v = u + at,

t = (v - u)/a

t= (0 - 30)/(-5.625)

t = 5.3333 sec

Answer:

Space in the astronomy and cosmology space is 3 dimensional region and earth atmosphere end is called space.

Explanation:

Space is the everything of the top earth atmosphere moon, starts, milky way, black hole and GPS satellites an distant,space also called between stars,moon,planet.

Space is all the extends far in all directions, space is finite unbound space surface of the earth has finite are no beginning or not end.

Space contains there are three dimensions is called 3 D space,an space is to refer an interval during signal transmitted also used by the character, bytes, words and octets in  digital signal.

space is that term can refer to various in science, communications and mathematics,and maintain orbits for responsible time, space is usually to begin at the lowest attitude satellites  can maintain orbits.

space coordinates are uniquely define the location of any particular point  and that continuum requires more than coordinates,and the number of dimensions and conventional space or digital communications during the  signal represents logic is 0 words in a digital signal.  

Answer:

Infrasound vs. Ultrasound: Infrasound is sound that is below the lower limit of human hearing, below 20 Hz, and ultrasound is above the upper limit of human hearing, above 20,000 Hz.  Individuals use infrasound - this recurrence run for checking seismic tremors and volcanoes, graphing rock and oil developments underneath the earth. Infrasound is described by a capacity to get around hindrances with little scattering.  

For instance, a few creatures, for example, whales, elephants and giraffes convey utilizing infrasound over significant distances. Torrential slides, volcanoes, seismic tremors, sea waves, water falls and meteors produce infrasonic waves. Symptomatic ultrasound, additionally called sonography or demonstrative clinical sonography, is an imaging technique that utilizes high-recurrence sound waves to create pictures of structures inside your body. The pictures can give important data to diagnosing and treating an assortment of ailments and conditions.

Explanation:

idk how many words this is but its a start for u to add on to and i hope this helps and its in my own words - pls mark me brainiest

Answer:

The hypothesis may or may not be true and needs to be tested. It might be the answer to the problem. Hence, it must be tested thoroughly. When these predictions are tested again and again in independent scientific experiments and gets verified, the hypothesis is converted into a scientific theory.

this process is called parellelogram method of resolving vectors.

Answer:

The angular frequency of the block is ω = 5.64 rad/s

Explanation:

The speed of the block v = rω where r = amplitude of the oscillation and ω = angular frequency of the oscillation.

Now ω = v/r since v = speed of the block = 62 cm/s and r = the amplitude of the oscillation = 11 cm.

The angular frequency of the oscillation ω is

ω = v/r

ω = 62 cm/s ÷ 11 cm

ω = 5.64 rad/s

So, the angular frequency of the block is ω = 5.64 rad/s

Answer:

12.5 m/s

Explanation:

a = Δv / Δt

2.5 m/s² = Δv / 5 s

Δv = 12.5 m/s