when is the acceleration of a body is positive, negative and zero?

Answers

Answer 1

Answer:

In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration

Explanation:

Answer 2

Answer:

The acceleration is positive when it's in the same direction as that of velocity. It keeps on increasing the velocity. In this case, velocity is not constant.

The acceleration is negative when it is in the direction opposite to that of velocity. It keeps on decreasing the speed of body.

The acceleration is zero when the body moves with a constant velocity in any particular direction.


Related Questions

A force of 6 N is used to open a door, wherein the distance of the force to the axis of rotation is 80 cm. If the angular acceleration it acquires is 0.5 rad/s 2, determine the moment of inertia of the door.

Answers

Explanation:

∑τ = Iα

(6 N) (0.80 m) = I (0.5 rad/s²)

I = 9.6 kg m²

differences between concave and convex meniscus​

Answers

Explanation:

A concave meniscus,(normally seen) occurs when the molecules of the liquid are attracted to those of the container. This occurs with water and a glass tube. A convex meniscus occurs when the molecules have a stronger attraction to each other than to the container, as with mercury and glass.

Answer:

there are differences between concave and convex menuscus

Explanation:

A concave meniscus, which is what you normally will see, occurs when the molecules of the liquid are attracted to those of the container. This occurs with water and a glass tube. A convex meniscus occurs when the molecules have a stronger attraction to each other than to the container, as with mercury and glass.

Which describes refraction? *

10 points

O

Refracted rays travel through a boundary into a new medium.

O

The angle of incidence is the same for angle of refraction

Refracted rays change direction and go back to the original medium

Answers

Answer:

Refracted rays travel through a boundary into a new medium.

Explanation:

Refracted rays travel through a boundary into a new medium. is only true for refraction.

The angle of incidence is the same for angle of refraction, is not true for refraction. Refraction follows Snell's law, states that ratio of the sine of the angle of refraction and the sine of the angle of incidence is always constant and equivalent to the ratio of phase velocities of the two mediums it is passing through.

Refracted rays change direction and go back to the original medium is false for refraction however, it is true for reflection.

The coil of wire in the center of the screen encompasses an area through which magnetic field lines pass, so there is a magnetic flux through those coils. With the magnet stationary, is this magnetic flux producing any flow of current or potential difference?

Answers

Answer:

No, the coil will produce no flow of current or potential difference.

Explanation:

Magnetic field flux is the number of magnetic field line passing through a given area. It depends on the area and the magnetic field strength through this area. For electromagnetic induction to occur, there must be a constantly changing magnetic field. This is according to Faraday's law of electromagnetic induction that states that the induced EMF is directly proportional to the rate of change in flux ΔФ/Δt, and is also proportional to the number of turns on the coil. A changing magnetic field will lead to a break in the flux linkage, which induces current or potential difference on the coil. A stationary coil through a magnetic filed will therefore produce no electric flow of current or potential difference on the coil.

A 28-turn circular coil of radius 4.40 cm and resistance 1.00 Ω is placed in a magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression B = 0.010 0t + 0.040 0t2, where B is in teslas and t is in seconds. Calculate the induced emf in the coil at t = 4.20 s.

Answers

Answer:

ε = -0.0589V = -58.9mV

Explanation:

In order to calculate the induced emf in the coil, you use the following formula:

[tex]\epsilon=-N\frac{d\Phi_B}{dt}=-N\frac{d(SBcos\alpha)}{dt}[/tex]         (1)

ε: induced emf = ?

N: turns of the coil = 28

ФB: magnetic flux trough the coil

S: cross sectional area of the circular coil = π.r^2

r: radius of the cross sectional area of the coil = 4.40cm = 0.044m

B: magnetic field

α: angle between the direction of the magnetic field and the direction of the normal to the cross area of the coil = 0°

You take into account that the area is constant respect to the magnetic field that cross it. Only the magnetic field is changing with time. The magnetic field depends on time as follow:

[tex]B(t)=0.010t+0.040t^2[/tex]           (2)

You replace the expression (2) into the equation (1), evaluate the derivative, and replace the values of the other parameters for t =4.20s:

[tex]\epsilon=-NS\frac{dB}{dt}=-NS\frac{d}{dt}[0.010t+0.040t^2]\\\\\epsilon(t)=-NS(0.010+0.080t)\\\\\epsilon(t)=-(28)(\pi(0.044m)^2)(0.010T/s+0.080T/s^2(4.20s))\\\\\epsilon(t)=-0.0589V=-58.9mV[/tex]

The induced emf in the coil is -58.9mV

Samuel applies a horizontal force of 35.0 N to a sleigh over a distance of 1.50 m along a level surface. Calculate the work done on the sleigh by samuel. show your work.

Answers

Answer:

52.5 J

Explanation:

Work done (W) is the product of the force (F) applied on a body and the distance (s) moved in the direction of the force.

i.e W = F × s

It is a scalar quantity and measured in Joules (J).

Given that: F = 35.0 N and s = 1.50 m, then;

W = F × s

W = 35.0 × 1.5

   = 52.5 J

Therefore, the work done on the sleigh by Samuel is 52.5 J.

What is the formula for calculating the efficiency of a heat engine? Answers:

Answers

Efficiency of heat engine is determined by the ratio of difference in temperature of cold from hot reservoir to the temperature of hot reservoir over temperature of hot reservoir.

Pluto was first observed in 1930, and its largest moon, Charon, was discovered in 1978. A few years after Charon’s discovery, astronomers were able to observe a series of eclipses as Pluto and Charon passed in front of one another. By studying how the brightness of Pluto and Charon changed as they eclipsed each other, astronomers were able to measure the masses and radii of both Pluto and its moon. What did these measurements imply about the average densities of Pluto and Charon?

Answers

Answer:

The average densities of both matches the expected density for objects made from water ice.

Explanation:

Charon's density is 1.2 to 1.3 g / cm3, while Pluto's density is 1.8 to 2.1 g / cm3. This was discovered in many researches and measurements of these two celestial bodies, with the objective of understanding them and promoting efficient scientific knowledge.

With the measurements of the average densities between pluto and Charon it was possible to conclude several statements about them. Firstly, it is possible to see that the two formed independently and at different times, in addition to indicating the existence of few rocks in charon, which is consistent with the average density of objects made mostly of water ice.

A body is acted upon by a force of 4N.
As a result, the velocity of the body has
changed from 0.3 m/s to 0.1 m/s passing
through a certain distance. If the mass
of the body is 1 kg, find the distance travelled.

Answers

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Kinematics.

so here we get as,

V^2 = U^2 + 2as

so here, a = -0.2 m/s^2

(0.1)^2 = (0.3)^2 + (-0.2)(s)

=> 0.01 = 0.09 - 0.2s

=> 0.2s = 0.08

=> s = 0.08/0.2

=> s = 0.4 m

Will Mark Brainliest if Correct PLZ!!!!! A bullet is shot at some angle above the horizontal at an initial velocity of 87m/s on a level surface. It travels in the air for 13.6 seconds before it strikes the ground 760 m from the shooter. At what angle above the horizontal was the bullet fired? Round to the nearest whole number and include units in your answer Use g= -9.8 m/s2 for the acceleration of gravity.

Answers

Answer:

≅50°

Explanation:

We have a bullet flying through the air with only gravity pulling it down, so let's use one of our kinematic equations:

Δx=V₀t+at²/2

And since we're using Δx, V₀ should really be the initial velocity in the x-direction. So:

Δx=(V₀cosθ)t+at²/2

Now luckily we are given everything we need to solve (or you found the info before posting here):

Δx=760 mV₀=87 m/st=13.6 sa=g=-9.8 m/s²; however, at 760 m, the acceleration of the bullet is 0 because it has already hit the ground at this point!

With that we can plug the values in to get:

[tex]760=(87)(cos\theta )(13.6)+\frac{(0)(13.6^{2}) }{2}[/tex]

[tex]760=(1183.2)(cos\theta)[/tex]

[tex]cos\theta=\frac{760}{1183.2}[/tex]

[tex]\theta=cos^{-1}(\frac{760}{1183.2})\approx50^{o}[/tex]


Where is the energy in a glucose molecule stored?

Answers

Answer:

Energy is stored in the bonds between atoms

Answer:

Energy is stored in the bonds between atoms

Explanation:

Ape-x

A 22.8 kg rocking chair begins to slide across the carpet when the push reaches 57.0 N. What is the coefficient of static friction?​

Answers

Answer:

0.255

Explanation:

The following data were obtained from the question:

Force (F) = 57 N

Mass (m) = 22.8 Kg

Coefficient of static friction (µ) =...?

Next, we shall determine the normal reaction (R). This is illustrated below:

Mass (m) = 22.8 Kg

Acceleration due to gravity (g) = 9.8 m/s²

Normal reaction (R) =?

R = mg

R = 22.8 x 9.8

R = 223.44 N

Finally, we can obtain the coefficient of static friction (µ) as follow:

Force (F) = 57 N

Normal reaction (R) = 223.44 N

Coefficient of static friction (µ) =...?

F = µR

57 = µ x 223.44

Divide both side by 223.44

µ = 57/223.44

µ = 0.255

Therefore, the coefficient of static friction (µ) is 0.255.

Answer:

.255

Explanation:

I'm also on acellus and it's the right answer

5. A bus starting from rest accelerates in a straight line at a constant rate of 3m/s2 for 8s. Calculate the distance travelled by the bus during this time interval.

Answers

Answer:

d = 96 meters

Explanation:

a = acceleration

t = time

d = distance

[tex]d = \frac{1}{2} \times a \times {t}^{2} [/tex]

[tex]d = \frac{1}{2} \times 3 \times {8}^{2} [/tex]

[tex]d = 96[/tex]

how does an electric iron work when the power is on​

Answers

Answer:

The basic principle on which the electric iron works is that when a current is passed through a piece of wire, the wire heats up. This heat is distributed to the sole (base) plate of the electric iron through conduction.

Ratio of acceleration due to grabity and universal gravitational constant

Answers

Answer:

acceleration due to gravity = 9.8m/s^2

universal gravitational constant= 6.67×10 ^_11 nm^2 kg_2

now, ratio=9.8/6.67×10^_11.

A box of mass 4.5 kg is pushed across a rough surface (μK = 0.18) for a distance of 2.0 m by a constant force of 10 N. If the object reaches a speed of 2.0 m/s by the end of the push, what was its speed at the beginning of the push?

Answers

Answer:

Explanation:

  Work done by force applied = force x displacement

= 10 x 2 = 20 J

Negative work done by frictional force

= μ mg x d where μ is coefficient of kinetic friction , m is mass and d is displacement

= - .18 x 4.5 x 9.8 x 2

= - 15.87 J

Net positive work done on the mass = 4.13 J

If v was the initial velocity

increase in kinetic energy = positive work done on mass

= 1 / 2 m v² - 1/2 m u² = 4.13 where v is final and u is initial velocity

1 /2 x 4.5 x 2 ² - 1/2 x 4.5 u² = 4.13

9 - 2.25 u² = 4.13

2.25 u² = 4.87

u² = 2.16

u = 1.47 m /s .

A car speeds over a hill past point A, as shown in the figure. What is the maximum speed the car can have at point A such that its tires will not leave the track? Round to one decimal place and include units. Image:

Answers

Answer:

see explanations below

Explanation:

At the point when the car leaves the track, the reaction on the road is zero, meaning that the centrifugal force equals the gravitation force, namely

mv^2/r = mg

Solve for v in SI units

v^2 = gr = 9.81 m/s^2 * 14.2 m = 139.302 m^2/s^2

v = sqrt(139.302) = 11.8 m/s

Answer: at 11.8 m/s (26.4 mph) car will leave the track.

Un automovil circula a 126km/h por una autopista. Su conductor observa que a 150 m delante de el, se encuentra un árbol caído que ocupa toda la calzada. Inmediatamente presiona los frenos con una aceleración de -3,5 m/s². Determinar si logra evitar el choque.

Answers

Answer:

El conductor no puede evitar el choque.

Explanation:

Primero, convierta la velocidad del conductor a m / s:

1 km/h = 0.277778 m/s

126 km/h = 126 * 0.277778 = 35 m/s

La velocidad del automóvil es de 35 m / s.

El conductor presiona los frenos con una aceleración de -3.5 m / s² para evitar un choque a 150 m por delante.

Veamos qué distancia se moverá el automóvil después de que comience a desacelerar.

Utilizaremos una de las ecuaciones de movimiento lineal de Newton:

[tex]v^2 = u^2 + 2as[/tex]

donde v = velocidad final = 0 m / s (el automóvil debe detenerse)

u = velocidad inicial = 35 m / s

a = aceleración = -3.5 m / s².

s = distancia recorrida

Por lo tanto:

[tex]0 = 35^2 + (2 * -3.5 * s)\\\\=> 1225 = 7.0s\\\\s = 1225 / 7 = 175 m[/tex]

Esto significa que el automóvil se detendrá a 175 m.

Por lo tanto, a esa velocidad y aceleración, el conductor chocará contra el árbol caído porque el automóvil no podrá detenerse antes de alcanzar la posición del árbol.

A drop
of
oil volume 10 m
Spreads out on water to make a
Circular fils of diameter 10
What is that thickness?​

Answers

Answer:

[tex]27.5\ m[/tex]

Explanation:

As we know that volume of cylinder is

[tex]v=\pi r^{2} *h[/tex]

Where v=volume , h= height or thickness and r= radius

Here,

[tex]v= 10 m ,\ diameter= 10, \ r=\frac{diameter}{2} \ r=\frac{10}{2}\\ r=5[/tex]

Putting these values in the previous equation , we get

[tex]10\ = \frac{22}{7} *5 *5*h\\ 14\ =\ 110*h\\h=\frac{110}{14} \\h=\frac{55}{2} \\\\h=27.5\ m[/tex]

Therefore thickness is 27.5 m

0.0000302 in scientific notation

Answers

The answer is 3.02 x 10^-5

Answer:

3.02x10^-5

Explanation:

A scientific notation consists of

c x 10^n

the c must be a number between 1-9, while n must be an integer.

it indicates the c being multiplied by the nth power of 10.

From 0.0000302, we need to move the decimal to after 3 so that 3.02 can be a number between 1-9. When moving the decimal point to the right side, each digit moved counts as -1 power of 10.

So, to give 3.02, we need to move the decimal by 5 digits. hence, we can conclude n = -5.

0.0000302 = 3.02x10^-5

A gas is held at atmospheric pressure, approximately 100kPa, and room temperature, 298K,
in a container closed with a piston. The piston is initially in a fixed position so the container has a volume of 2.0dm3.
The gas is heated to a temperature of 100∘C
What is the pressure in the container?

Answers

Answer:

125 KPa

Explanation:

Data obtained from the question include:

Initial pressure (P1) = 100 KPa

Initial temperature (T1) = 298 K

Final temperature (T2) = 100°C = 100°C + 273 = 373 K

Final pressure (P2) =..?

Since the volume of the container is fixed, the final pressure in the container can be obtained as follow:

P1/T1 = P2/T2

100/298 = P2/373

Cross multiply

298 x P2 = 100 x 373

Divide both side by 298

P2 = (100 x 373) / 298

P2 = 125.2 ≈ 125 KPa

Therefore, the final pressure in the container is approximately 125 KPa.

Derive the following equations for uniformly accelerated motion by graphical method. a) Velocity -time relation b) Position - time relation 3) Position – velocity relation.

Answers

Answer:

a) velocity - time realation

that graph's gradient gives the uniform acceleration

a disc starts from rest with an angular acceleration completes 10 revolutions in 2 seconds. the time taken by it to complete 10 more revolution from that instant is​

Answers

Starting from rest, the disc completes [tex]\theta[/tex] revolutions after [tex]t[/tex] seconds according to

[tex]\theta=\dfrac\alpha2t^2[/tex]

with angular acceleration [tex]\alpha[/tex]. It completes 10 rev in 2 s, which means

[tex]10\,\mathrm{rev}=\dfrac\alpha2(2\,\mathrm s)^2\implies\alpha=5\dfrac{\rm rev}{\mathrm s^2}[/tex]

Find the time it takes to complete 20 rev with this acceleration:

[tex]20\,\mathrm{rev}=\dfrac12\left(5\dfrac{\rm rev}{\mathrm s^2}\right)t^2\implies t=\sqrt8\,\mathrm s\approx2.83\,\mathrm s[/tex]

so it takes approximately 0.83 s to complete 10 more rev.

What is electronic configuration?​

Answers

Answer:

Electronic Configuration is the distribution of electrons in sub shells (s,p,d,f).

For Example,

The electronic configuration of Carbon (6 electrons) is [tex]1s^22s^22p^2[/tex]

An apple falls out of a tree from a height of 2.3 m What is the impact speed of the apple?

Answers

Answer:

6.72 m/s

Explanation:

recall that the equations of motion may be expressed as

v² = u² + 2as

where,

v = final velocity,

u = initial velocity = 0 m/s because it is stationary before it starts falling

a = acceleration (in this case because it is falling, it is the acceleration due to gravity = 9.81 m/s²)

s = distance traveled = 2.3m

in our case, if we neglect air resistance, then we simply substitute the known values above into the equation of motion.

v² = u² + 2as

v² = 0² + 2(9.81)(2.3)

v² = 45.126

v = √45.126

v = 6.72 m/s

shes right it is 6.71 m/s

Why is it advisable not to look directly at the Sun? Please Give scientific reason for your answer

Answers

This sunlight can flood your retinas, overstimulating the rods and cones that sense light and causing them to release chemicals that can damage the retinas. This condition is known as solar retinopathy, and it can cause permanent eye damage.

Answer:

your eyes would get seriously damaged

Explanation:

when you look directly at the sun, the sun shines it's rays directly to your eyes , which damage them. that's why you should always wear sunglasses in that type of weather, and never point directly at the sun. if you find this answer helpful, mark it as brainliest.

Convert Gravitational constant (G) = 6.67×10^-11 Nm²kg^-2 to cm³ g ^-1 s^-2.

Answers

Answer:

6.67×10⁻⁸ cm³/g/s²

Explanation:

6.67×10⁻¹¹ Nm²/kg²

= 6.67×10⁻¹¹ (kg m/s²) m²/kg²

= 6.67×10⁻¹¹ m³/kg/s²

= 6.67×10⁻¹¹ m³/kg/s² × (100 cm/m)³ × (1 kg / 1000 g)

= 6.67×10⁻⁸ cm³/g/s²

Is Einstein's equation E=mc^2 is applicable on our earth if it is not why?is it applicable in space can a body moves through speed of light

Answers

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◦•●◉✿What does E mc2 actually mean?

E = mc2. It's the world's most famous equation, but what does it really mean? "Energy equals mass times the speed of light squared." On the most basic level, the equation says that energy and mass (matter) are interchangeable; they are different forms of the same thing.✿◉●•◦

WILL GIVE BRANLIET PLS HELP!!!!! AT LEAST TAKE A LOOK!!!!! I REALLY COULD USE THE HELP!!! SHARE YO SMARTNESSS!!! Upon using Thomas Young’s double-slit experiment to obtain measurements, the following data were obtained. Use these data to determine the wavelength of light being used to create the interference pattern. Do this using three different methods. The angle to the eighth maximum is 1.12°. The distance from the slits to the screen is 302.0 cm. The distance from the central maximum to the fifth minimum is 3.33 cm. The distance between the slits is 0.000250 m.

Answers

Answer:

λ = 6,108 10⁻⁷ m = 610.8 nm

λ = 5.513 10⁻⁷ m = 551.3 nm

Explanation:

Young's double slit experiment results in a pattern consisting of maxima and minima of interference, the maximums are described by the expression

          d sin θ = m λ

where d of the distance between the two slits, θ is the angle from the central maximum to the given interference line, λ the wavelength of the radiation and an integer indicating the order of interference

In this exercise they give us several conditions

The first

the angle is 1.12º to the maximum m = 8

the distance between the slits d = 0.000250 m

of the initial equation

           λ = d sin θ / m

           λ = 0.000250 sin 1.12 / 8

           λ = 6,108 10⁻⁷ m = 610.8 nm

The second

the distance from the slits to the screen is L = 302.0 cm = 3.020 m

the distance from the central maximum is y = 3.33 cm = 0.0333 m for interference m = 5

in this case we use that the angle in the experiment is small

      tan θ = y / L

      tan θ = sin θ / cos θ = sin θ

we substitute

       sin θ = y / L

       d y / L = m λ

       λ = d y / L m

 

we calculate

       λ = 0.000250 0.0333 / (3,020 5)

       λ = 5.513 10⁻⁷ m = 551.3 nm

What is the meaning of refraction​

Answers

Answer:

A change of direction that light undergoes when it enters a medium with a different density from the one through which it has been traveling.

Answer:

the fact or phenomenon of light radio waves etc being deflected in passing obliquely through the interface between one ,medium and another or through a medium of varying density

Explanation:

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