Rotational Motion and Law of Gravity

It looks like you need to use the concept of torque, which is the product of the force and the distance from the point of rotation. You may also need to use trigonometry to break the force into its horizontal and vertical components. Can you try setting up the equations and see if you can solve for the torque? Let me know if you need any further assistance.
  • #1
madeeeeee
87
0
a) Two objects attract each other with a gravitational force of magnitude 9.30 x10-9 N when separated by 19.4 cm. If the total mass of the objects is 5.06 kg, what is the mass of each?

Heavier mass_______kg
Lighter mass______ kg

my attempt:
F=Gm1m2/r^2
so I rearranged to get m1 and m2 by itself and got (r^2)(F)/G=m1m2
5.247598=m1m2
but how do I get the mass for m1 and m2 separately is m1 + m2 = 5.06 kg?


b) A dental bracket exerts a horizontal force of 86.2 N on a tooth at point B in the figure. What is the torque on the root of the tooth about point A? (PLEASE SEE THE ATTACHMENT FOR THE PICTURE)

I know I need to break the forces up into components but I am lost on this question. Please help me! Thank you
 

Attachments

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  • #2
madeeeeee said:
a) Two objects attract each other with a gravitational force of magnitude 9.30 x10-9 N when separated by 19.4 cm. If the total mass of the objects is 5.06 kg, what is the mass of each?

Heavier mass_______kg
Lighter mass______ kg

my attempt:
F=Gm1m2/r^2
so I rearranged to get m1 and m2 by itself and got (r^2)(F)/G=m1m2
5.247598=m1m2
but how do I get the mass for m1 and m2 separately is m1 + m2 = 5.06 kg?

Yes, the total mass is given as 5.06 kg, so m1 + m2 = 5.06 kg. Replace one of the masses, say m2, with m2 = (5.06 kg - m1).
 
  • #3
I used this and found my answer to be .433 and 4.627 but its wrong. Do i have my formula correct?
 
  • #4
madeeeeee said:
I used this and found my answer to be .433 and 4.627 but its wrong. Do i have my formula correct?

Your formula (Newton's law of gravitation) looks okay. Perhaps something went wrong in your math manipulations. If you post your calculations they can be checked.
 
  • #5
actually I just solved it! It was just a silly error! But thank you for your help

Do you have nay idea how to do part b ?
 
  • #6
madeeeeee said:
actually I just solved it! It was just a silly error! But thank you for your help

Do you have nay idea how to do part b ?

What are your thoughts? What do you think you need to know in order to proceed?
 

FAQ: Rotational Motion and Law of Gravity

What is rotational motion?

Rotational motion is the movement of an object in a circular or curved path around a fixed point or axis. This type of motion involves the rotation of an object around its center of mass.

How is rotational motion different from linear motion?

Rotational motion involves movement around a fixed point or axis, while linear motion involves movement in a straight line. In rotational motion, the object maintains a constant distance from the axis of rotation, while in linear motion, the object travels a specific distance in a straight line.

What is the law of gravity?

The law of gravity, also known as Newton's law of universal gravitation, states that every particle in the universe is attracted to every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

How does the law of gravity affect rotational motion?

The law of gravity plays a crucial role in rotational motion by providing the centripetal force that keeps an object moving in a circular path. This force is necessary to counteract the natural tendency of an object to move in a straight line and ensures that the object maintains a circular motion around an axis.

Can the law of gravity be applied to all objects in the universe?

Yes, the law of gravity applies to all objects in the universe, regardless of their mass or size. This law is one of the fundamental principles of physics and has been proven to accurately describe the motion of celestial bodies, as well as objects on Earth.

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