A good diet. and exersise is the answer
Answer:
C. her moment of inertia increases and her angular speed decreases
D. her moment of inertia increases and her angular speed decreases
Explanation:
The moment of inertia of a body is the sum of the products of an increment of mass and the square of its distance from the center of rotation. When a spinning person extends her arms, part of her mass increases its distance from the center of rotation, so increases the moment of inertia.
The kinetic energy of a spinning body is jointly proportional to the moment of inertia and the square of the angular speed. Hence an increase in moment of inertia will result in a decrease in angular speed unless there is a change in the rotational kinetic energy.
This effect is used by figure skaters to increase their spin rate by drawing their arms and legs closer to the axis of rotation. Similarly, they can slow the spin by extending arms and legs.
When the person extends her arms, her moment of inertia increases and her angular speed decreases.
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<em>Note to those looking for a letter answer</em>
Both choices C and D have identical (correct) wording the way the problem is presented here. You will need to check carefully the wording in any problem you may think is similar.
The momentum of a fast object compared to that of a slow object even if they both have the same mass, is their velocities.
Having same mass but different velocities results in different momentum.
Example: mass = 10kg
Velocity 1 = 50 Velocity 2 = 100
Momentum 1 = 10×50 = 500 Ns
Momentum 2 = 10×100 = 1000 Ns
Hope it helped!
Answer: Magnitude of electric field = 6.77×10^11N/C
Explanation: Electric field= E =KQ/ r ^2
Given:
Total charge Q=53.2nc
Radius 84cm= 0.84m
Coulombs constant K= 8.987x10^9NmC^-1
E =(( 8.987×10^9) × 53.2) /(0.84^2)
E = ( 4 . 777 ×10 ^ 9 )/ 0.7056
E = 6.77 × 10^ 11 NC^-1
Note:
1 A (armstrong) = 10⁻¹⁰ m
1 nm (nanometer) = 10⁻⁹ m
Given:
Radius of a krypton atom = 1.9 A = 1.9 x 10⁻¹⁰ m
Part (a)
Answer: 0.019 nm
Part (b)
The diameter of a krypton atom = 2*1.9A = 3.8 A = 3.8 x 10⁻¹⁰ m.
The number of krypton atoms within a length of 1.0 mm is
Answer: About 2.632 x 10⁶ atoms
Part (c)
The radius of a krypton atom is
1.9 A = (1.9 x 10⁻¹⁰ m)*(10² cm/m) = 1.9 x 10⁻⁸ cm
The volume of a krypton atm is
Answer: 2.873 x 10⁻²³ cm³
