Question

Give reasons.
1)Tip of minute hand of a clock is in accelarated motion
2)The gravitional force between earth and sun is said tobe doing zero work done.
3)Plastic coating is used on metalic conductors.​

Answer 1

Answer:

The work done by the moon when it revolves around the earth is zero because here displacement of moon and gravitational force of earth are perpendicular to each other.

i.e., Work done (W) =F×d×cosθ

where F = applied force

d = displacement of the body

θ = angle between the applied force and the displacement of the body

In the case of revolution of moon around the earth, θ is 90°. Thus, W=F×d×cos90°

= F×d×0=0

So, the work done by the moon when it revolves around the earth is zero.

mark me brain list

Answer 2

Answer:

1. It actually points towards the center of circle (fixed end of minutes hand). This linear acceleration is called centripetal acceleration. So it is accelerated motion also.

2.Work done is equal to zero assuming earth revolves around the sun in a perfect circle.

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθ

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degree

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degree

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degreeCos90

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degreeCos90 o

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degreeCos90 o =0

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degreeCos90 o =0Thereby F∗S∗cos90=F∗S∗0=0

done is equal to zero assuming earth revolves around the sun in a perfect circle.As Work=Force∗Displacement∗cosθWhere θ is the angle between force and displacement .In this case θ=90degreeAs centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degreeCos90 o =0Thereby F∗S∗cos90=F∗S∗0=0HENCE NO WORK IS done

3. Most electrical wire is covered in a rubber or plastic coating called insulation. ... The purpose of insulation covering the metal part of an electrical wire is to prevent accidental contact with other conductors of electricity, which might result in an unintentional electric current through those other conductors.