A man stands still on a moving walkway that is going at a speed of 0.2 m/s to
the west. What is the velocity of the man according to a stationary observer?
A. 0.2 m/s north
B. 0.2 m/s west
C. 0.2 m/s South
D. 0.2 m/s east

Answer:

27.34 (no unit)

Explanation:

26.975*82.33%+29.018*17.67%

=27.34

Answer:

1.7 BTU

Explanation:

q = mCΔT

q = (25 g) (0.9 J/g/°C) (100°C − 20°C)

q = 1800 J

q = 1800 J × (1 BTU / 1055 J)

q = 1.7 BTU

Answer:

(a) 0.42 m/s²

(b) 83 N

Explanation:

Assuming g = 10 m/s².

Draw free body diagrams for the child and the chair.

There are three forces on the child:

Tension force T pulling up,

Weight force Mg pulling down,

and normal force N pushing up.

There are three forces on the chair:

Tension force T pulling up,

Weight force mg pulling down,

and normal force N pushing down.

Sum of forces on the child in the y direction:

∑F = ma

T + N − Mg = Ma

Sum of forces on the chair in the y direction:

∑F = ma

T − N − mg = ma

Add the equations together to find the acceleration.

2T − Mg − mg = Ma + ma

a = (2T − Mg − mg) / (M + m)

a = g (2T − Mg − mg) / (Mg + mg)

a = (10 m/s²) (2 × 250 N − 320 N − 160 N) / (320 N + 160 N)

a = 0.42 m/s²

Plug into either equation to find the normal force.

T + N − Mg = Ma

250 N + N − 320 N = (320 N / 10 m/s²) (0.42 m/s²)

N = 83 N

Answer:

The velocity at that time would be [tex](-67.975\; \rm s)[/tex]. The velocity of this particle is continuously changing.

Explanation:

Differentiate the expression for position [tex]x[/tex] with respect to time [tex]t[/tex] to find an expression for velocity.

[tex]\begin{aligned}v(t) &= \frac{d}{dt}[x(t)] \\ &= \frac{d}{dt} \left[ 7.4 + 9.2\, t - 2.1\, t^{3}\right]\\ &= 9.2 - 6.3\, t^{2}\end{aligned}[/tex].

Hence, at [tex]t = 3.5\; \rm s[/tex], velocity would be [tex]v(3.5) = 9.2 - 6.3 \times (3.5)^{2} = -67.975\; \rm m[/tex].

Since velocity [tex]v(t)[/tex] changes with time [tex]t[/tex], the velocity of this particle is continuously changing.

Answer:

[tex]\Large \boxed{\mathrm{5.67 \ seconds }}[/tex]

Explanation:

[tex]\displaystyle \mathrm{acceleration \ = \ \frac{final \ velocity - initial \ velocity }{elapsed \ time}}[/tex]

[tex]\displaystyle A \ = \ \frac{V_f - V_i }{t}[/tex]

[tex]\displaystyle 3 \ = \ \frac{25 - 8 }{t}[/tex]

[tex]\displaystyle 3 \ = \ \frac{17 }{t}[/tex]

[tex]\displaystyle t \ = \ \frac{17 }{3} \approx 5.67[/tex]

Almost 3 times fast than normal pulley system

mark me

Answer:

Explanation:

[tex]m =800kg\\v = 15\\\\K.E = \frac{1}{2}mv^2\\ K.E= \frac{1}{2} \times 800\times 15^2\\= 400 \times 225\\= 90000 joules\\= 90 kilojoules[/tex]

Answer:

Those reaction in which one element replaces another element form its place is called Single displacement reaction

Answer:

it will be 8ms-1

Explanation:

MaUa+MbUb=MaVa+MbVb

Answer:

8 atm

Explanation:

Ideal gas law:

PV = nRT

where P is pressure, V is volume, n is moles, R is universal gas constant, and T is absolute temperature.

If n is constant:

PV / T = PV / T

(4 atm) (60 L) / (27 + 273) K = P (40 L) / (127 + 273) K

0.8 atm = 0.1 P

P = 8 atm

Answer:Testing

Explanation:Once a scientist has made a hypothesis, what would they typically do TESTING nextn

Once a scientist has made a hypothesis, they would typically do testing, therefore the correct answer is option B

Scientific claims are statements made in science based on an experiment.

These Scientific claims are backed by the experimental data and their true results obtained from scientific investigation and experimentation.

When a scientist performs a fair test is one in which all other circumstances are maintained while just one variable is changed at a time.

Scientists frequently discover that their hypotheses and predictions were not supported by the results of their experiments. In these situations, they will communicate the findings of their experiment before revising their original hypotheses and predictions in light of the new knowledge they have gained.

The right response is option B because once a scientist has made a theory, they usually do testing.

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Answer:

Humans naturally have what's known as binaural hearing, which is the ability to hear in two ears.

Answer:

pull

Explanation:

because when you push there is one component of force that adds to tge weight of body and hence there is more friction. Whwn you pull the vertical component of force is against the weight of body and hence friction is low.

Answer:

The derivative of a constant term is always 0. So the acceleration of the body would be zero. Hence, the acceleration of a body moving with uniform velocity will always be zero.

Mercury in a glass tube.

Answer:

Upthrust = 20 N

Explanation:

The question says that "A body weighs 100N in air and 80N when submerged in water. Calculate the upthrust acting on the body ?"

Upthrust is defined as the force when a body is submerged in liquid, then liquid applies a force on it.

ATQ,

Weight of body in air is 100 N

Weight of body in water is 80 N

Upthrust is equal to the weight of body in air minus weight of body in water.

Upthrust = 100 N - 80 N

Upthrust = 20 N

So, 20 N of upthrust is acting on the body.

To calculate the density of a substance, its mass and volume has to be determined. So that:

i. For the milk in the carton, its mass and volume should be known.

ii. For the two objects given in the question, their individual masses and volumes have to be determined.

Density of a substance (ρ) is the rate of the mass (m) of the substance to its volume (V). It is measure in kg/[tex]m^{3}[/tex].

i.e ρ = [tex]\frac{m}{V}[/tex]

The density of a substance can be determined once the mass and its volume have been accurately measured.

1. How to measure the density of the contents of a milk carton.

a. Determine the mass of the milk carton with its content.

b. Determine the mass of the milk carton when empty.

c. Subtract the mass of the milk carton when empty from the mass of the carton with its content. This will give the mass of the milk in the carton.

d. Using a beaker, measure the volume of the milk.

e. Divide the mass of the milk by its volume to determine its density.

2. How to measure the densities of two objects of equal mass.

a. Fill an Eureka's can or a beaker with sprout with water to its brim.

b. Slowly drop the mass into the beaker with water so as to collect the volume of the liquid displaced into another beaker.

c. The volume of the liquid displaced is the volume of the mass.

d. Divide the mass of the object by its volume to determine its density.

NB: These procedures are observed to determine the densities of the two object individually.

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Answer:

[tex]\large \boxed{\mathrm{40 \ Nm}}[/tex]

Explanation:

[tex]\sf Moment \ (Nm) = Force \ (N) \times Distance \ from \ pivot \ (m)[/tex]

[tex]M=20 \times 2[/tex]

[tex]M=40[/tex]

Answer:

○ 0 [tex]\checkmark[/tex]

Explanation:

Even if the athelete runs four laps of a 400 m track, its displacement will be 0 because the displacement is the shortest distance from its to final position. And, here the final and initial position is same since he comes to its initial position after covering certain distance. So, displacement is 0.

Explanation:

speeds = distance/time

=100/16

=6.25m/s

second speed is;

400/44 =9.09

av. speed = total speed /n

= (6.25+9.09)/2

=7.67 m/s

Answer:

20 m

Explanation:

The ball travels 4 m up, then 16 m down.  It travels a total distance of 20 m.

The computer model would rely on the labeled pH values of various hand soap brands however the labled pH value might not be entirely accurate, which could comprise the accuracy of the computer model.

Inaccuracies in the simulation's underlying chemistry model could be a potential source of mistake in an experiment involving the pH values of several liquid hand soap solutions and water.

The outcomes could differ from actual behavior if the model does not adequately represent the intricate chemical interactions that control pH fluctuations. Furthermore, because they might not exactly match the varied properties of real hand soap solutions, the simulation's assumptions and parameters could introduce bias. Disparities between simulation results and empirical findings may also result from inadequate consideration of temperature impacts and ambient factors. To reduce such possible mistakes, careful simulation validation against empirical data and chemistry model modification are required.

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Explanation:

To find the average of these numbers, we just have to add the three numbers together and divide by 3.

Answer:

For two resistors R1 = 12Ω and R2 = 18Ω are connected in series. The equivalent resistance R12 of the circuit can take any of the values

Answer:

I guess i would say the microscope

Explanation:

Because of the microscope, we can see the cells.

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:

The answer is (a.) An upward force balances the downward force gravity on the skydiver

The skydiver is falling at a constant velocity because the upward force is balancing the downward force of gravity. According to Newton, the opposite force balance each other. This is stated in Newton's second law of motion.

The statement that best applies Newton’s laws of motion to explain the skydiver’s motion is that An upward force balances the downward force of gravity on the skydiver.

Newton's 3rd law often applies to skydiving.

When gravity is not acting upon the skydivers they would continue moving in the direction the vehicle they jumped from was moving.

If no air resistance takes place, then the skydivers would still accelerating at 9.8 m/s until they hit the ground.

The skydiver after leaving the aircraft will accelerates downwards due to the force of gravity

usually as there is no air resistance acting in the upwards direction, and there is a resultant force acting downwards, the skydiver will accelerates towards the ground.

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Answer and Explanation:

Data provided in the question

Force = 50N

Length = 5mm

diameter = 2.0m = [tex]2\times 10^{-3}[/tex]

Extended by = 0.25mm = [tex]0.25\times 10^{-3}[/tex]

Based on the above information, the calculation is as follows

a. The Stress of the wire is

[tex]= \frac{force\ applied}{area\ of \ circle}[/tex]

here area of circle = perpendicular to the are i.e cross-sectional  i.e

= [tex]\frac{\pi d^{2}}{4}[/tex]

= [tex]\frac{\pi(2\times 10^{-3})^2}{4}[/tex]

Now place these above values to the above formula

[tex]= \frac{4\times 50}{\pi\times 4 \times 10^{-6}} \\\\ = \frac{50}{\pi}[/tex]

= 15.92 MPa

As 1Pa = 1 by N m^2

So,

MPa = 10^6 N m^2

b. Now the strain of the wire is

[tex]= \frac{Change\ in\ length}{initial\ length} \\\\ = \frac{0.25\times 10^{-3}}{5}[/tex]

= [tex]5 \times 10^{-5}[/tex]

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:

atmospheric pressure

b)

c)increases

d) ....