e. write unit of the following physical quantities

Answer:

Explanation:

The negative only matters reallly if you are dealing with a 2d system. I could even define down as positive and up as negative. However, usually you are taught that down is negative. It really doesn't matter because a force is a force. It is only given a direction relative to another force or vector direction.

Answer:

Explanation:

(a)

In event A , one has to walk along diameter of the field from X to Y.

In this event , walk is along a straight line , both displacement and distance covered will be same.

Distance = displacement = 1 km.

option ii is correct .

(b )

radius of circular track r = 0.5 km

length of track = circumference = 2π r

= 2 x 3.14 x .5 = 3.14 km

Length of running in event B is 15.7 km

No of rounds = 15.7 / 3.14 = 5

option iii is correct .

( c )

speed = length of race / time

time = length of race / speed

= 15. 7 km / 3.14 km /h

= 5 hours .

option iv is correct option.

(d)

In event C , length of race is 25.12 km

speed = length of race / time taken

= 25.12 km  / 4 hour

= 6.28 km/h .

Option i is correct.

Answer:

(a) (ii)

(b) (iv)

(c) (i)

(d) (i)

Explanation:

diameter, XY = 1 km

Event A- Fast walking along the diameter of the field.

Event B- A 15.7 km running race along the circular track.

Event C- A 25.12 km cycling race along the circular track.

(a) When athletes walked from X to Y , the distance is equal to the displacement which is equal to the diameter = 1 km.  

Option (ii).

(b) distance = 15.7 km

distance traveled by one round = 3.14 x 1 = 3.14 km

So, the number of round complete in B = 1.57/3.14 = 0.5

option (iv).

(c)If Pihu ran at an average speed of 3.14 km/h during Event B, then she would finish the race in

time, t = 1.57/3.14 = 0.5 hours

option (i)

(d) What should the average speed of cyclist Yousef be, so that he can complete Event C in 4hours?

Distance = 25.12 km

time , t = 4 hours

Speed = 25.12 / 4 = 6.28 km/h

Option (i)

Answer:

Gamma rays

Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies.

Answer:

2) zero acceleration

Explanation:

Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.

This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.

Mathematically, the motion of an object is described in terms of time, distance, speed, velocity, position, displacement, acceleration, etc.

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

Generally, an object is said to be in equilibrium when neither the energy possessed by the object not state of motion changes with respect to time. Thus, the vector sum of all the forces acting upon an object that's in equilibrium is zero.

In conclusion, an essential characteristic of an object in equilibrium is zero (0) acceleration because there's no change in its velocity with respect to time.

Answer:

(i) The particle has a period of 0.3 seconds.

(ii) The angular velocity of the particle is a20.944 radians per second.

(iii) The linear velocity of the particle is 1.047 meters per second.

(iv) The linear acceleration of the particle is 21.933 meters per square second.

Explanation:

Statement is incomplete and have mistakes, complete and correct form is presented below:

A particle makes 800 revolutions in 4 minutes of a circle with a radius of 5 centimeters. Find (i) its period, (ii) its angular velocity, (iii) its linear velocity and (iv) its acceleration.

(i) The period of the particle ([tex]T[/tex]), in seconds, is the time taken to make a complete revolution:

[tex]T = \frac{4\,min \times \frac{60\,s}{1\,min} }{800\,rev}[/tex]

[tex]T = 0.3\,s[/tex]

The particle has a period of 0.3 seconds.

(ii) The angular velocity ([tex]\omega[/tex]), in radians per second, is determined by the following formula:

[tex]\omega = \frac{2\pi}{T}[/tex] (1)

[tex]\omega = \frac{2\pi}{0.3\,s}[/tex]

[tex]\omega \approx 20.944\,\frac{rad}{s}[/tex]

The angular velocity of the particle is a20.944 radians per second.

(iii) The linear velocity ([tex]v[/tex]), in meters per second, is calculated by the following formula:

[tex]v = R\cdot \omega[/tex] (2)

Where [tex]R[/tex] is the radius of the circle, in meters.

If we know that [tex]R = 0.05\,m[/tex] and [tex]\omega \approx 20.944\,\frac{rad}{s}[/tex], then the linear velocity of the particle is:

[tex]v = (0.05\,m)\cdot \left(20.944\,\frac{rad}{s} \right)[/tex]

[tex]v = 1.047\,\frac{m}{s}[/tex]

The linear velocity of the particle is 1.047 meters per second.

(iv) Since angular velocity is constant, linear acceleration of the particle ([tex]a[/tex]), in meters per square second, is entirely radial. Acceleration can be found by means of this expression:

[tex]a = \omega^{2}\cdot R[/tex] (3)

If we know that [tex]R = 0.05\,m[/tex] and [tex]\omega \approx 20.944\,\frac{rad}{s}[/tex], then the linear acceleration of the particle is:

[tex]a = \left(20.944\,\frac{rad}{s} \right)^{2}\cdot (0.05\,m)[/tex]

[tex]a = 21.933\,\frac{m}{s^{2}}[/tex]

The linear acceleration of the particle is 21.933 meters per square second.

Answer:

Explanation:

-Cambio de temperatura

Al calentar un cuerpo la temperatura aumenta

Es el efecto más inmediato del calor, el aumento de la temperatura. Al calentar un cuerpo, es habitual, aunque no siempre, que el cuerpo aumente de temperatura. El aumento dependerá de la cantidad de calor que se suministra, del tipo de sustancia y de su cantidad.

-Dilatación

Cuando un objeto se calienta, su volumen aumenta. Este fenómeno se llama dilatación térmica. Por el contrario, cuando un objeto se enfría, su volumen disminuye, debido a la contracción térmica.

Cuando se calienta un cuerpo, además de cambiar de estado o variar su temperatura, también cambia su tamaño, se dilata.

Por ejemplo, los puentes no se construyen de una única pieza, sino que suelen presentar uno o varios cortes longitudinales, las llamadas juntas de dilatación. Si no existieran esas juntas, los cambios de longitud del puente entre el invierno y el verano o entre el día y la noche acabarían por romperlo.

La dilatación de un cuerpo dependerá del aumento de temperatura que experimente, de su tamaño y de la sustancia de que esté hecho. Cuanto más aumente la temperatura más aumentará su tamaño, lo mismo que cuanto mayor sea, mayor se hará.

Todos los cuerpos, ya sean sólidos, líquidos o gaseosos, varían su tamaño cuando intercambian calor con otro cuerpo.

-Cambios de estado:

Si una sustancia modifica el estado de sólido, líquido o gaseoso, se produce un cambio de estado. Un cambio de estado es una modificación en la forma en que se disponen las partículas que constituyen una sustancia.

El estado en que se encuentre un cuerpo depende de la presión a la que está sometido y de su temperatura. Para cambiar su estado se debe modificar alguna de estas variables, o ambas. Al elevar la temperatura de una sustancia sólida, aumenta la agitación de sus partículas.

Answer:

All forms of matter (solid, liquid and gas) undergo expansion on heating. When a solid is heated, the atoms gain energy and vibrate more vigorously. This results in the expansion of the solid. For a given change in temperature, the extent of expansion is smaller in solids than in liquids and gases. This is due to the rigid nature of solids.

Explanation:

Magnetic force between the north poles of two magnets is REPULSIVE

Answer:Repulsion or attraction

Explanation:The angle between the compass needle   and geographic north is called the MAGNETIC DECLINATION.(see earth:the magnetic field of the earth ). The repulsion or attraction between two magnetic dipoles can be viewed as the interaction of one dipole with the magnetic field produced by other dipole.

Answer:

The goal of physics is to understand how things work from first principles. ... Courses in physics reveal the mathematical beauty of the universe at scales ranging from subatomic to cosmological. Studying physics strengthens quantitative reasoning and problem solving skills that are valuable in areas beyond physics.

Answer:

Explanation:

The dimension less constants are the constants having no dimensions and also have a constant value.

For example, 1, 2, 3... numbers, e (exponent), [tex]\pi[/tex], etc.

The dimension less variables are the variables having no dimensions.

For example, refractive index, angle, strain, etc.

Answer:

B

Explanation:

Stress-strain diagram with 4 materials graphed. The graph with maximum yield strength is B.

Stress is defined as the force applied per unit area of cross-section. It is denoted by Sigma(σ). Its's unit is same as the pressure i.e. N/m².

Considering the stress-strain diagram shown here. Assumed all four material samples denoted as (A-D) were originally the same size and shape.

When a body is stretched by a tensile force, it stretches more and more until it reaches its elastic limit. There comes a point where the body no longer stretches. The change in stress is very less and the stress is greater at the yield point. The strength required up to the yield point is called as the yield strength. The body breaks while forming the neck of the bottle. This strength of any material is known as ultimate stress at break or ultimate tensile strength.

So, the material with the highest yield strength is B.

Thus, the correct option is B.

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Answer:

The distance of car form the mirror is 330 cm.

Explanation:

height of object, h = 140 cm

height of image, h' = 14 cm

radius of curvature, R = 60 cm

focal length, f = R/2 = + 30 cm

Let the distance of image is v and the distance of object is u.

[tex]\frac{h'}{h}\frac{v}{u}\\\\\frac{14}{140} =\frac{v}{u}\\\\v =\frac{u}{10}[/tex]

Use the formula of focal length

[tex]\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\\\\\frac{1}{30}=\frac{10}{u}+\frac{1}{u}\\\\\frac{1}{30}=\frac{11}{u}\\\\u = 330 cm[/tex]

Let h be the height of the water in the tube. Then the total volume of water is

(h m) (1 m²) = h m³

After dropping the ball into the water, the height of the water changes to

h m + 2.25 mm = (h + 0.0025) m

and so the contents of the tub take up (h + 0.0025) m³ of volume.

This means the ball displaces

(h + 0.0025) m³ - h m³ = 0.0025 m³

of water, which is to say that this is volume of the ball.

With a mass of 4 kg, you would find its density to be

(4 kg) / (0.0025 m³) = (4 kg) / (2.5 L) = 1.6 kg/L

Group of answer choices.

A. Energy is absorbed in the reaction.

B. Energy is released in the reaction.

C. There is no transfer of energy in the reaction.

D. Energy is lost in the reaction.

Answer:

B. Energy is released in the reaction.

Explanation:

A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.

Basically, there are two (2) main types of chemical reaction and these include;

I. Endothermic reaction: it's a chemical reaction in which heat is absorbed

II. Exothermic reaction: it's a chemical reaction in which heat is liberated into the environment.

In Chemistry, all chemical equation must follow or be in accordance with the Law of Conservation of Mass, which states that mass can neither be created nor destroyed by either a physical transformation or a chemical reaction but transformed from one form to another in an isolated (closed) system.

Generally, energy is released in a chemical reaction when the energy of the products is less than the energy of the reactants and it is referred to as an exothermic reaction.

However, when the energy of the products is greater than the energy of the reactants, energy is absorbed and it is referred to as an endothermic reaction.

Complete Question:

The density of aluminium is 2.70g/cm³. The thickness of a rectangular sheet of aluminium foil varies, but is much less than 1 mm.

A student wishes to find the average thickness. She obtain the following measurements

Mass of sheet = 60.7g

Length of sheet = 50.0cm

Width of sheet = 30.0 cm

Calculate the student's values for

(i) the volume of the sheet

(ii) the average thickness of the sheet

Answer:

Thickness = 0.015 cm

Explanation:

Given the following data;

I. To find the volume of the sheet;

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the formula;

[tex] Density = \frac {mass}{volume} [/tex]

Making volume the subject of formula, we have;

[tex] Volume = \frac {mass}{density} [/tex]

Substituting into the formula, we have;

[tex] Volume = \frac {60.7}{2.70} [/tex]

Volume = 22.48 cm³

II. Volume = length * width * height

But, height = thickness

Volume = length * width * thickness

22.48 = 50 * 30 * thickness

22.48 = 1500 * thickness

[tex] Thickness = \frac {22.48}{1500} [/tex]

Thickness = 0.015 cm

Conversion:

1 mm = 0.1 cm

X mm = 0.015 cm

X = 0.015/0.1 = 0.15 mm

Therefore, the thickness of the rectangular sheet of aluminium foil is less than 1 millimetre.

Answer:

time.

Explanation:

Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.

This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.

A reference point refers to a location or physical object from which the motion (movement) of another physical object or body can be determined.

Mathematically, the motion of an object is described in terms of acceleration, time, distance, speed, velocity, position, displacement, etc.

A graph can be defined as the graphical representation of data (informations) on horizontal and vertical lines i.e x-axis and y-axis respectively.

A position-time (x-t) graph is a graph of the position of an object against (versus) time.

To make a position-time graph, you should plot the values of the position of an object or body with respect to the starting point on the y-axis against the corresponding time on the x-axis.

Generally, the slope of the line of a position-time (x-t) graph is typically used to determine or calculate the velocity of an object.

An instantaneous velocity can be defined as the rate of change in position of an object in motion for a short-specified interval of time. Thus, an instantaneous velocity is a quantity that can be found by measuring the slope of a line that is tangent to a point on the graph.

In conclusion, the x - t graph also referred to as the position-time graph is used for determining the instantaneous velocity from the slope.

Answer:

The work done is 12 MJ.

Explanation:

The engine of a car exerts a constant traction force of F=4000N . Assume that the car is moving at a constant speed of 36 km/hr. In five minutes, what is the work done by the engine's traction?

Force, F = 4000 N

speed, v = 36 km/h = 10 m/s

time , t = 5 minutes = 5 x 60 = 300  s

Work done is given by

W =  force x distance

W = 4000 x 10 x 300 J = 12 x 10^6 J = 12 MJ

Answer:

90 degree

Explanation:

Electric field line is vertical to the electric field line.

The angle between the field line and the equipotential where an electric field line crosses an equipotential surface is 90°

This is a region of space around a charged particle, or between two voltages.

The angle between Electric field crosses an equi-potential surface is always 90 degrees. When the potential becomes constant,the negative potential gradient also becomes zero, hence necessitating the need for Electric field to be always normal with surface.

Therefore, the angle between electric field and equi-potential surface is 90 degrees.

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Answer:

q = 2.65 10⁻⁶ C

Explanation:

For this exercise we use Coulomb's law

        F =[tex]k \frac{q_1q_2}{r^2}[/tex]

In this case they indicate that the load is of equal magnitude

       q₁ = q₂ = q

the force is attractive because the signs of the charges are opposite

       F = [tex]k \ \frac{q^2}{r^2}[/tex]

       q = [tex]\sqrt{\frac{F \ r^2}{k} }[/tex]

we calculate

        q = [tex]\sqrt{\frac{0.7 \ 0.3^2 }{9 \ 10^9} }[/tex]

        q = [tex]\sqrt{7 \ 10^{-12} }[/tex]Ra 7 10-12

        q = 2.65 10⁻⁶ C

Answer:

The maximum force is 1.8 N.

Explanation:

A pendulum is a vertically hanging spring with a stiffness of 30 N/m and a mass of 320 g. The excitable excitation oscillates vertically around the equilibrium position with an amplitude of 6 cm. Take g = 10m/s. The magnitude of the maximum pulling force of the distance from the suspension point during the oscillation of the weight is

stiffness, K = 30 n/m

mass, m = 320 g

amplitude, A = 6 cm = 0.06 m

g = 10 m/s^2

Let the maximum acceleration is a.

[tex]a = w^2 A\\\\a = \frac{K}{m}A\\\\Force, F = m a \\\\F = K A\\\\F = 30 \times 0.06 \\\\F = 1.8 N[/tex]

Answer:

physical measurement comprises the measurement of objects, things, etc. and is concerned with the measurement of height, weight, length, size, volume etc.

Answer:

t = 2.7 seconds

Explanation:

Given that,

Initial speed, u = 3.8 m/s

Final speed, v = 4.2 m/s

Acceleration of Michael, a = 0.15 m/s²

(a) Let t is the time taken by him to catch Robert. It can be calculated as follows :

[tex]a=\dfrac{v-u}{t}\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{4.2-3.8}{0.15}\\\\t=2.7\ s[/tex]

So, the time taken is 2.7 seconds.

Answer:

:) :::::::::::::::::::::::::::::::))))

Answer:

A

Explanation:

low credit score means its more risky to lend someone money

Answer:

D. more mass is concentrated.

Explanation:

Gravity is considered to be a universal force of attraction which acts between all objects that has both mass, energy and occupy space. Therefore, it acts in such a way as to bring objects together.

Additionally, the gravity of earth makes it possible for all physical objects to possess weight.

Newton's law of universal gravitation states that the force of attraction (gravity) acting between the Earth and all physical objects is directly proportional to the Earth's mass, directly proportional to the physical object's mass and inversely proportional to the square of the distance separating the Earth's center and that physical object.

Center of gravity can be defined as the specific point where all of the weight of an object is concentrated.

Generally, all the objects found around the world all have a center of gravity.

Additionally, when an object is balanced so that a displacement lowers its center of gravity, the object is said to be in stable equilibrium.

The centre of gravity of a physical object is usually located where more mass is concentrated in the physical object or body.

However, the location of the centre of gravity is subject to change and as such doesn't always remain the same.

Answer:

wrong answer because m=100

Explanation:

I think it is incorrect

Ah, I tried

Answer:

117.72 N

Explanation:

The given parameters are;

The mass m₁ = 2.0 × 10³ kg

The mass m₂ = 4.4 × 10² kg

The mass of the man, m₃ = 6.0 × 10 kg

The condition of the interaction of the surfaces = Frictionless surfaces

The

The tension in the string = The downward force = The weight of (m₂ + m₃) = (m₂ + m₃) × g

Let a represent the acceleration of the connected masses due to the weight of m₂, and m₃, we have;

(m₁ + m₂ + m₃) × a = (m₂ + m₃) × g

∴ a = (m₂ + m₃) × g/(m₁ + m₂ + m₃)

Which gives;

a = (4.4 × 10²+ 6.0 × 10) × 9.81/(2.0 × 10³+ 4.4 × 10²+ 6.0 × 10) = 1.962

The downward acceleration, a = 1.962 m/s²

The apparent weight of the man = The mass of the man, m₃ × The acceleration, a

∴ The apparent weight of the man = 6.0×10 kg ×1.962 m/s² = 117.72 N