Help with OCR physics A2 G484 newtons first law PLEASE!!!!!!

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imagine you are holding  a newton meter. a mass of 1kg hangs from the meter causing it to register 9.8N

what forces are acting on the mass? what are their values and directions?

you accelerate your hand upwards? what forces are acting on the mass during the acceleration? are their values equal in magnitude? explain?

you lower your hand steadily? " "

Posted Tue 11th September, 2012 @ 21:04 by Ashley Odili

1 Answer

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Hey There. 

Firstly, the reason for the mass of 1kg equaling 9.8N is thanks to gravity. As gravity is equal to 9.8m/s.

Already you have the answer to you're first question: "the forces acting upon the mass would be both gravity and you. Gravity is having a downward pull upon the mass of 9.8N where as you are having an upward force of 9.8N (this is according to Newtons first law "For every action there is an opposite and equal reaction")

The answer to question 2. As you are now lifting The mass upwards you are going against the force of gravity. The forces acting upon the mass are there for Gravity, the upward thrust from you, as well as air resistance (However this may be negligible) There Values are NOT equal, if there values were equal the mass would not move. to overcome the force of gravity you will have to have an up thrust of more than 9.8m/s.

To answer question 3: As you lower your hand you are allowing the force of gravity to have a greater influence over the object than the resistance of your hand.

I really hope this helps :D

Answered Tue 18th September, 2012 @ 12:49 by Jason Taylor