OpenStudy (anonymous):

Neglect the effect of rotation of earth. Suppose the earth suddenly stops attracting the objects placed near its surface. A person standing on the surface of the earth will 1) fly up 2) slip along the surface 3) fly along a tangent to the earth's surface 4) remain standing

OpenStudy (kc_kennylau):

Do we neglect also the revolution of earth around the sun?

OpenStudy (anonymous):

I don't know.

OpenStudy (aonz):

Im pretty sure its 3 :) Its the effect of centripetal motion

OpenStudy (kc_kennylau):

According to Newton's First Law, it will remain standing

OpenStudy (kc_kennylau):

@AonZ neglect rotation of earth

OpenStudy (anonymous):

how @kc_kennylau ??

OpenStudy (aonz):

Earths rotation around the sun is centripetal motion. Once the centripetal force is gone the person will fly off as a tangent

OpenStudy (kc_kennylau):

@Akhilender I'm not very good at physics, so @AonZ will explain it to you better, but I want to know whether we also consider the revolution of earth around the sun

OpenStudy (anonymous):

NO , revolution of earth around the sun is not considered.

OpenStudy (kc_kennylau):

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OpenStudy (kc_kennylau):

ok if it's not considered, the man would be standing still

OpenStudy (aonz):

Yea...

OpenStudy (anonymous):

Why?

OpenStudy (kc_kennylau):

Because of Newton's First Law.

OpenStudy (aonz):

I thought when it said neglect the rotation of Earth, it meant Earths rotation on its poles. If not however, Newtons 1st law of inertia states that an object will continue to stay at rest unless a force is acted upon it. Since there is no force the person will remain at rest

OpenStudy (anonymous):

forces acting on the person are 1) mg downwards, 2) N contact force upwards if g is abscent then only N will act. Therefore the person will fly up.

OpenStudy (kc_kennylau):

if g is absent, N will also not exist, since N is the reaction force (Newton's Third Law)

OpenStudy (kc_kennylau):

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OpenStudy (kc_kennylau):

OK let's picture this, suppose you have an electrical magnet. You suddenly turn off the magnet, the thing won't fly off anywhere will it

OpenStudy (anonymous):

reaction force will be acted by the person on the earth if action is the force applied by the earth on the person.

OpenStudy (anonymous):

I don't think Reaction force will be equal to mg. since reaction will not act on the same body . will it??

OpenStudy (kc_kennylau):

The reaction is due to the fact that mg is pulling a body down, and the table has to resist in order that the body do not penetrate into the table.

OpenStudy (anonymous):

yes you can equate it. But when g will be abscent the contact force will be up and person will up

OpenStudy (aonz):

If a person stands on Earth he will exert a force to Earth and Earth will exert the same force in the opposite direction. So, the reaction will act on the same body

OpenStudy (vincent-lyon.fr):

In this problem, Earth is orbiting the Sun. Sun's attraction is not neglected. Neglecting Earth's rotation is like standing at the Poles. Both you and the Earth are attracted in a quasi circular orbit by the Sun. Since path does not depend on mass, you would follow the same path as Earth around the Sun. Earth and you would be weightless relative to each other, just as an astronaut outside the space station remains on the same orbit as the station.

OpenStudy (vincent-lyon.fr):

So you would remain where you are, but contact with the ground would become zero, and you would be able to move by simply giving a small impulse.

OpenStudy (anonymous):

i hope fly up

OpenStudy (anonymous):

@Vincent-Lyon.Fr Why the contact force will be zero?? @AonZ One thing i'm very sure is that Action and reaction will never occur together on the same body.

OpenStudy (anonymous):

@Akhilender Contact force is normal force.. since there is no gravitational attraction between u and the earth, there is no Normal force, hence u would experience weightlessness