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No. A car exerts some force on the road and road exerts same force on the car but displacement of road is zero so work done by car on road is zero.

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Solution :*****************************************a) To make the block up the incline plane , force should be equal and opposite to the net force acting down the Incline plane.=μR+2g Sin30°=0.2 x (9.8)√3+2x9.8 x 1/2=3.39 +9.8=13Nwith this minimum force the body move up the incline with a constant velocity as net force acting on it is zero.

b)Net force acting down the incline plane is given by :F=2gsin30°-μR=2x9.8 x 1/2 -3.39=6.41 NDue to F=6.41 N the body will move down the incline plane with acceleration . Hence the force required is zero.

The work done by the force will be equal to the potentail energy gained by the mass.

Let L be the length of the string ,

F.d= MgL (1 -cos45 )

The horizontal displacement of the mass is d= L sin 45

F L sin45 = Mg L(1 - 45)

F = Mg (sq. root 2 - 1)

Ac = a×v = v/r×v = v²/r

option

option 4 speedAn object undergoinguniform circular motionis moving with aconstant speed.

Centripetal acceleration is a name given to the type of acceleration that causes the velocity of an object to change in a way such that it starts moving in a circular path. When the object is moving in circular path, the centripetal acceleration is directed from the object to the circle's centre (perpendicular to velocity). This is caused by a centripetal force that acts towards the centre of a circle. Centripetal force is a real force (it can be tension in string, gravitational, electrostatic, etc).

centrifugal force is a fictitious force. It doesn't really exist. We use the concept of centrifugal force to describe the motion of objects in a rotating frame of reference Centrifugal force: Imagine a circular ride in which a child sits on a horse and moves in a circle. We know that the rod holding the horse exerts a centripetal force to keep the horse moving in a circle, i.e. pulling force towards the centre of the circle.

They cant be said to be a reaction pair.However they are consequential pair.Consider this,

An object is tied to string and that string is fixed at other end.Now the object is moved in circular direction.Centrifugal force is that one which keeps the object moving and is trying to take that object in tangential direction at any given point.whereas centripetal force is stopping that to happen and is pulling the object towards center.To be right in physics term, centrifugal force is not a force at all, its resultant of inertia due to circular motion.

no.....

because centripetal ,is the net force.... towRds center...

And fugle is phuedo force....

a force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.

1.Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The laws of reflection are as follows:i).The incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane.ii).The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal.iii).The reflected ray and the incident ray are on the opposite sides of the normal.2.

Centripetal force isdefined as, “The componentof forceacting on a body in curvilinear motion thatisdirected toward the centerofcurvature or axisofrotation,” whilecentrifugal force isdefined as, “The apparentforce, equal and opposite to thecentripetal force, drawing a rotating body away from the centerof rotation.

Centripetal forceis theforceon an object on a circular path that keeps the object moving on the path. It is always directed towards the center and its magnitude is constant, based on the mass of the object, its tangential velocity, and the distance of the object (radius) from the center of the circular path.

Common Examples are

1.A ball , revolving in horizontal circle attached to a rope.

Think what happens if rope suddenly breaks.

2.A vehicle turning on the road.

3.Sattelites revolving around earth.

4.Planet bounded to Sun.

5.Electron motion.

6.Dryer in washing machine.

option (c) is correct.

UsingV = u + at0 = 30 + a*6a = - 5Force = m * a = 3 * (-5) = 15 N in opposite direction of motion.

Since position time graph has two points inflations.

so the answer is 2 times. option 3.

displacement will be total area of figure 1/2*2*2 + 1/2*2*1 - 1/2*1*2 + 1*1 = 2 + 1 - 1 + 1 = 3 cm

option 2

clear ni h

thnx

Area is directly proportional to T^4so (4) is correct

option 4 is right. it will be 4000K

By exposing the surface of metal to radiation of frequency greater than the threshold frequency for the metal.

is it right but question carrying 1 marks or 1 ward question.so please answer in 1 word

Logically, how can magnitude of vector sum be equal to difference​ of their magnitudes. Obviously if the vectors are in opposite directions. This means the angle has to be 180.

Mathematically,

Let the vectors beaandbwith magnitudes a and b respectively and the angle between them be x.

Magnitude of the sum of a and b is

√(a^2+b^2+2abcosx

Difference in their magnitudes is

a-b

Hence,

√(a^2+ b^2+2ab cosx) = a-b

Squaring both sides,

a^2+b^2+2ab cos x = a^2+ b^2–2ab

2ab cosx+2ab =0

2ab(cosx +1) =0

Since 2ab can't be zero,

Cos x+1=0

Cosx=-1

X=180

OPTION 2 is correct..

let the vector be i .. ans k be a negetive number = -2

now when k is multiplied.. with ithe vectors become = -2i = 2(-i)....so, direction of vector changes from i to -i...and magnitude changes k times..

The reason you feel weightless is because there is no force pushing against you, since you are not in contact with anything. Gravity is pulling equally on all the particles in your body. This creates a sensation where no forces are acting on you and you feel weightless. It would be the same sensation as if you were floating in space.

_____ of heat requires the object to be in contact

Some papers report in watts per centimeter-kelvin (W/(cm⋅K)). In imperial units, thermal conductivity is measured in BTU/(hr⋅ft⋅°F). The dimension of thermal conductivity isM1L1T−3Θ−1, expressed in terms of the dimensions mass (M), length (L), time (T), and temperature (Θ).

They can be determined as

Fx=Fcostheta=10*cos30=10*√3/2Fx= 5√3 N

Fy= Fsintheta=10*sin30=10*1/2=5 Nhence,these are required components

Thaks

Thedimension of thermal conductivityis M1L1T^−3Θ^−1

option 3

please sent solved answere

1.2m or120cm

uses of potentiometer

Comparison of emfs of the cells

Measurement of internal resistance of a cell

Measurement of small emfs like that in a thermocouple

Measurement of current flowing in a resistace

Comparison of resistances

so , option B is the answer.