Answer:
I would disagree with my friend because that according to Newton's first law, an object in motion will continue to be in motion until stopped by another object/force. If the object is already moving, it will stay in motion until something else stops it. There is no need for a force to be <em>continually</em> applied to it while it's already moving.
Use the conservation of angular momentum; angular momentum at the beginning = angular momentum at the end
Conservation of angular momentum:
I1 w1 = I2 w2
Where I is the moment of inertia. For a sphere, I=2/5 m R^2. Substituting into the equation above we get
w2 = I1 w1 / I2 = w1 m1 R1^2 / (m2 R2^2)
w2 = w1 4 * (R1/R2)^2
= 4*(1)*(7E5/7.5)^2
= 3.48E10 revs/(17days)
= 2.04705882 x 10^9 revs/sec
Answer:
Explanation:
Given
mass of sphere 
diameter of sphere 
radius 
friction will provide resisting torque so
where 
(b)time taken to decrease its rotational speed by 
Answer:
The uncertainty in the position of the electron is 
Explanation:
The Heisenberg uncertainty principle is defined as:
≥ 
(1)
Where 
is the uncertainty in momentum, 
is the uncertainty in position and h is the Planck's constant.
The momentum is defined as:
(2)
Therefore, equation 2 can be replaced in equation 1
≥
Since, the mass of the electron is constant, v will be the one with an associated uncertainty.
≥ (3)
Then, can be isolated from equation 3
≥ 
(4)
But 
Hence, the uncertainty in the position of the electron is
