Because mass does not change from place to place but weight does change from place to place... why? because weight is the amount of gravitational force on an object and mass is the amount of matter in an object. mars has less gravitational force so an object will weigh less than it really weighs there
You know that when the displacement is equal to the amplitude (A), the velocity is zero, which implies that the kinetic energy (KE) is zeero, so the total mechanical energy (ME) is the potential energy (PE).
And you know that the potential energy, PE, is [ 1/2 ] k (x^2)
Then, use x = A, to calculate the PE in the point where ME = PE.
ME = PE = [1/2] k (A)^2.
At half of the amplitude, x = A/2 => PE = [ 1/2] k (A/2)^2
=> PE = [1/4] { [1/2]k(A)^2 } = .[1/4] ME
So, if PE is 1/4 of ME, KE is 3/4 of ME.
And the answer is 3/4
Question 18: a
question 19: b
question 20: c
Answer:
The tangential speed at Livermore is approximately 284.001 meters per second.
Explanation:
Let suppose that the Earth rotates at constant speed, the tangential speed (
), measured in meters per second, at Livermore (37.6819º N, 121º W) is determined by the following expression:
(1)
Where:
- Rotation time, measured in seconds.
- Radius of the Earth, measured in meters.
- Latitude of the city above the Equator, measured in sexagesimal degrees.
If we know that 
, 
and 
, then the tangential speed at Livermore is:
The tangential speed at Livermore is approximately 284.001 meters per second.
