An object is positively charged if it has more what​

Answer:

The speed of projection is 34 m/s.

Explanation:

Height of building, h = 51 m

horizontal distance, d = 74 m

time, t = 8 s

Let the angle is A and the speed is u.

d = u cos A x t

74 = u cos A x 8

u cos A = 9.25 .... (1)

Use second equation of motion

[tex]h = u sin A t - 0.5 gt^2\\\\-51 = u sinA \times 8 - 0.5\times 9.8\times8\times 8\\\\u sin A = 32.8 .... (2)[/tex]

Squaring and adding both the equations

[tex]u^2 = 9.25^2 + 32.8^2 \\\\u = 34 m/s[/tex]

Explanation:

Given that,

The radius of rain drop, r = 0.12 cm = 0.0012 m

The viscocity of air is, [tex]\eta=18\times 10^{-5}\ poise[/tex]

Let the viscous force is, [tex]F = 0.010173\ N[/tex]

The viscous force is given by :

[tex]F=6\pi \eta rv\\\\v=\dfrac{F}{6\pi \eta r}[/tex]

Put all the values,

[tex]v=\dfrac{0.010173}{6\pi 18\times 10^{-5}\times 0.0012 }\\\\v=2498.58\ m/s[/tex]

Answer:

a liquid warms gas cools

b solid piece warms and liquid cools

Answer:

[b] it id heated from 4o

Explanation:

Answer:

both swings at the same place

Explanation:

because there mother is giving same amount of force to both.

Answer:

98 J

Explanation:

Applying,

Change in kinetic energy = Final kinetic energy- initial kinetic energy

ΔK.E = mv²/2-mu²/2..............Equation 1

Where ΔK.E = Change in kinetic energy, m = mass of the box, u = initial velocity of the box, v = final velocity of the box.

From the question,

Given: m = 4.0 kg, u = 0 m/s, v = 7 ,0 m/s

Substitute these values into equation 1

ΔK.E = (4(7²)/2)-(4(0²)/2)

ΔK.E = (2×49)-0

ΔK.E = 98 J

Hence the change in kinetic energy 98 J

Answer:

Distance

Explanation:

Work can be defined as the energy transferred to a physical object by exertion of a force on the object to cause a displacement of the object. Thus, work is typically done when a person or simple machine move an object over a distance through the application of a force.

Mathematically, work done is given by the formula;

[tex] W = F * d[/tex]

Where,

W is the work done

F represents the force acting on a body.

d represents the distance covered by the body.

A dependent variable is the event expected to change when an independent variable is manipulated.

Hence, distance is the dependent variable because its value changes with respect to the amount of force exerted on an object.

Answer:

arge number of electrons free to move between the charged ions in the lattice.

Explanation:

The metallic bond occurs when an atom with few electrons is united in its last level, therefore the best way to decrease the total energy of the system is to lose all its electrons to remain with the configuration of a noble gas. The electrons that it loses cannot be acquired by other atoms since they all have few electrons, thus leaving a large number of electrons free to move between the charged ions in the lattice.

Some important characteristics emerge from this description of the metallic bond:

* It has many free electrons therefore its electrical conductivity is high

* As the charged ions are fixed, the material can be malleable, bent without breaking since the free electrons create the bond that keeps the system stable.

* As the electrons are free when heating a part of the material, these electrons acquire energy and rapidly propagate it to the other side, giving a high thermal conductivity

* As the temperature increases, the electrons acquire more kinetic energy, which is why there are more collisions between them and consequently the resistivity of the material increases.

Answer:

The right solution is "4.8° east of north".

Explanation:

Given:

Distance,

= 500 km

Speed,

[tex]\vec{v}=120 \ m/s[/tex]

Wind (towards west),

[tex]v_0=10 \ m/s[/tex]

According to the question, we get

The angle will be:

⇒ [tex]\Theta=Cos^{-1}(\frac{v_0}{v_1} )[/tex]

       [tex]=Cos^{-1}(\frac{10}{120} )[/tex]

       [tex]=85.21[/tex] (north of east)

hence,

The direction must be:

⇒ [tex]\Theta'=90-85.21[/tex]

        [tex]=4.79^{\circ}[/tex]

or,

        [tex]=4.8^{\circ}[/tex] (east of north)

Answer:

[tex]F = 14.2 N[/tex]  

Explanation:

From the question we are told that:

Mass [tex]m=0.15kg[/tex]

Radius [tex]r=0.6[/tex]

Angular Velocity [tex]\omega=2rev/s[/tex]

                            [tex]\omega= =2x2 \pi rad/s=>4 \pi rad/s[/tex]

Generally the equation for Force applied is mathematically given by

 [tex]F =mrw2[/tex]

 [tex]F=0.15*0.6* (4*x3.14^)2[/tex]

 [tex]F = 14.2 N[/tex]    

Answer:

P = 1.4 W

Explanation:

Given that,

The work done or the energy of the battery, E = 10,000 J

Time, t = 2 h

We need to find the power consumption. Let it is P. Power is the rate of doing work. So,

[tex]P=\dfrac{W}{t}\\\\P=\dfrac{10,000}{2\times 3600}\\\\P=1.38\ W[/tex]

or

P = 1.4 W

So, the power of the battery is 1.4 W.

Answer:

(a) 81.54 N

(b) 570.75 J

(c) - 570.75 J

(d) 0 J, 0 J

(e) 0 J  

Explanation:

mass of crate, m = 32 kg

distance, s = 7 m

coefficient of friction = 0.26

(a) As it is moving with constant velocity so the force applied is equal to the friction force.

F = 0.26 x m x g = 0.26 x 32 x 9.8 = 81.54 N

(b) The work done on the crate

W = F x s = 81.54 x 7 = 570.75 J

(c) Work done by the friction

W' = - W = - 570.75 J

(d) Work done by the normal force

W'' = m g cos 90 = 0 J

Work done by the gravity

Wg = m g cos 90 = 0 J

(e) The total work done is

Wnet = W + W' + W'' + Wg = 570.75 - 570.75 + 0 = 0 J  

The speed is in feet per seconds so change the length of the field from yards to feet.

1 yard = 3 feet

100 yards x 3 = 300 feet

The field is 300 feet long

Time = distance / speed

Time = 300 feet / 5 feet per second = 60 seconds = 1 minute

It will take 1 minute

Answer:

A person will take 60 Seconds to walk the distance of 100 yards.

Explanation:

Data Given ;

Distance ( d ) = 100 yards = 300 Ft

Speed ( v ) = 5 Ft/s

Time ( t ) = ?

The distance travelled in unit time is called speed.

formula ; [tex]v = \frac{d}{t} \\[/tex]

On putting values,

[tex]5 = \frac{300}{t}[/tex]

[tex]t =\frac{300}{5}[/tex]

[tex]t = 60 sec[/tex]

Hence the time taken by the person is 60 sec.

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Answer:

The answer is below

Explanation:

The intensity level (B) of a sound wave is given by:

B = 10log(I/I₀);

where I₀ is the threshold intensity = 1 * 10⁻¹² W/m², I is the intensity at distance 5 m, B is the intensity level = 52 dB

Substituting gives:

[tex]52=10log(\frac{I}{10^{-12}} )\\\\log(\frac{I}{10^{-12}} )=5.2\\\\I=1.58*10^{-7}\ W/m^2[/tex]

The pressure is given by:

[tex]I=\frac{p_{max}^2}{2\rho v} \\\\\rho=air\ density=1.2\ kg/m^3,v=speed\ of\ sound\ in\ air=344\ m/s,p_{max}=pressure:\\\\p_{max}=\sqrt{2\rho vI}=\sqrt{2*1.58*10^{-7}*1.2*344} =1.14*10^{-2}Pa[/tex]

Answer:

Example:Opening of a bottle cap by tool

when we hold a tool and open the bottle cap this is because , force x tool force .

The load arm is usually shorter than the effort arm in second order levers. Moving a large weight hence requires less effort. A force multiplier lever or effort multiplier lever is the name for this kind of lever. A boat's oars, for instance, can increase the force.

Second-order levers are devices with the input force farthest from the fulcrum and the output force on the same side of the fulcrum. A wheelbarrow is an excellent illustration of a second-order lever.

A second-order lever will have an output force greater than an input force, similar to first-order levers. The output journey, however, will be shorter than the input length. Both the input and output forces in this situation will move in the same direction.

Learn more about lever here:

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Answer:

False.

Explanation:

Suppose that we have an object that moves with constant acceleration A.

Then the acceleration of the object is defined by the equation:

a(t) = A

The acceleration is the rate of change of the velocity, then the velocity equation is given by the integration of the acceleration equation, we will get:

v(t) = A*t + V₀

Where V₀ is the velocity of the object at the time t = 0s.

Now, if we integrate it again, we will get the position equation:

p(t) = (1/2)*A*t^2 + V₀*t + P₀

Where P₀ is the initial position equation.

Here, we can see that the position equation is a quadratic equation (not a linear equation), then the statement is false.

Answer:

We need, mass, gravity and height.

Explanation:

When a body falls freely from a height, its initial velocity is zero, but due to the height it has some potential energy at the top and the kinetic energy is zero.

As it falls, the potential energy is gradually converted in to the kinetic energy so that the total energy of the falling body is conserved.

At the time as the body strikes the ground, the entire potential energy is converted into the kinetic energy.

Potential energy is given by

U = m g h

where, m is the mass, g is the gravity and h is the height,

So, to get the kinetic energy we require mass, gravity and height of the body.

Answer:

First of all the formula is F= uR,( force= static friction× reaction)

mass= 5+25=30

F= 50

R= mg(30×10)=300

u= ?

F=UR

u= F/R

u= 50/300=0.17N

[tex]4.8 \times 10^8[/tex] volts

Explanation:

The electric potential due to a point charge is given by

[tex]V= \dfrac{1}{4 \pi \varepsilon_{0}} \dfrac{Q}{r}[/tex]

where Q = charge = [tex]16 \times 10^{-9}[/tex] C

r = distance from a point = [tex]3 \times 10^{-3}[/tex] m

[tex]\varepsilon_{0}[/tex] = permitivity of free space

= 8.85×10^-12 C^2/N-m^2

Plugging in the numbers,

[tex]V = \dfrac{1}{4 \pi (8.85 \times 10^{-12})} \dfrac{16 \times 10{-9}}{3 \times 10^{-3}}[/tex]

[tex]= 4.8 \times 10^8[/tex] volts

Answer:

Option (b) is correct.

Explanation:

The amount of heat required to raise the temperature of substance of mass 1 kg by 1 degree C, is called specific heat of the substance.

The formula of the specific heat is

H = m c (T' - T)

where, m is the mass, c is the specific heat and T' - T is the change in temperature.

So, to know the rise in temperature, by adding the known amount of heat, the specific heat is required.

So, option (b) is correct.

Answer:

Thus, [tex]\frac{1 rev}{min} =\frac{2\pi}{60} rad/s[/tex]

Explanation:

The angular speed is defined as the rate of change of angular velocity.

Its SI unit is rad/s and other units are rev/min or rev/s.

[tex]\frac{1 rev}{min } = \frac{1 rev}{60 sec}\\\\1 rev = 2\pi rad\\\\So\\\\\frac{1 rev}{min} = \frac{2\pi}{60} rad/s[/tex]

Answer:

The induced current is counter clockwise if the current is decreasing and towards right.

Explanation:

When the current is decreasing in the wire, the direction of magnetic field at the center of the loop is outwards to the plane of paper which is given by the Maxwell's right hand thumb rule. The magnetic field is decreasing in nature.

So according to the Lenz's law, the induced current is such that which opposes the cause of its production, so that the induced current is counter clockwise.

Answer:

The right solution is:

(a) 2.87 eV

(b) 1.4375 eV

Explanation:

Given:

Wavelength,

= 433 nm

Potential difference,

= 1.43 V

Now,

(a)

The energy of photon will be:

E = [tex]\frac{6.626\times 10^{-34}\times 3\times 10^8}{433\times 10^{-9}}[/tex]

  = [tex]4.59\times 10^{-19} \ J[/tex]

or,

  = [tex]\frac{4.59\times 10^{-19}}{1.6\times 10^{-19}}[/tex]

  = [tex]2.87 \ eV[/tex]

(b)

As we know,

⇒ [tex]Vq=\frac{hc}{\lambda}-\Phi_0[/tex]

By substituting the values, we get

⇒ [tex]1.43\times 1.6\times 10^{19}=\frac{6.626\times 10^{-34}\times 3\times 10^8}{433\times 10^{-9}}-\Phi_0[/tex]

⇒                       [tex]\Phi_0=2.3\times 10^{-19} \ J[/tex]

or,

⇒                            [tex]=\frac{2.3\times 10^{-19}}{1.6\times 10^{-19}}[/tex]

⇒                            [tex]=1.4375 \ eV[/tex]

When we exhale, 90% waste material is Carbon Dioxide ( CO2 ) , so, it gets exhaled out in the form of CO2 rich air and it gets removed from the body, therefore our internal body becomes more pure and helps in making our internal temperature constant at a suitable level.

Answer:

Changes in climate conditions, especially the warming of global temperatures increases the likelihood of weather-related natural disasters. ... This is most visible when seen through changes in the intensity and frequency of droughts, storms, floods, extreme temperatures and wildfires.

Answer:

(a) Positive

(b) Electron gains energy as it moves from A to B.

Explanation:

VA = 260 V

VB = 210 V

An electron moves from lower to higher potential which is negatively charged and a positively charged particle moves  from higher to lower potential, so the charge particle is positive in nature.

(a) Positive

(b) No, electron gains energy as it moves from A to B.

Answer:

[tex]V_2=3.3m/s[/tex]

Explanation:

From the question we are told that:

Distance [tex]d_1=1.4m[/tex]

Tangential speed [tex]V=2.2m/s[/tex]

Distance 2 [tex]d_2=2.1m[/tex]

Generally the equation for Angular velocity is mathematically given by

 [tex]w=\frac{v}{r}[/tex]

Therefore

 [tex]\frac{v_1}{r_1}=\frac{v_2}{r_2}[/tex]

 [tex]V_2=\frac{2.2*2.1}{1.4}[/tex]

 [tex]V_2=3.3m/s[/tex]

Answer:

D I think I’m not for sure

Explanation: