"A pendulum is pulled back from its equilibrium (center) position and then released. When the pendulum bob is halfway between th
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Answer:
Assuming that both mass here move horizontally on a frictionless surface, and that this spring follows Hooke's Law, then the mass of would be four times that of
.
Explanation:
In general, if the mass in a spring-mass system moves horizontally on a frictionless surface, and that the spring follows Hooke's Law, then
.
Here's how this statement can be concluded from the equations for a simple harmonic motion (SHM.)
In an SHM, if the period is , then the angular velocity of the SHM would be
.
Assume that the mass starts with a zero displacement and a positive velocity. If represent the amplitude of the SHM, then the displacement of the mass at time
would be:
.
The velocity of the mass at time would be:
.
The acceleration of the mass at time would be:
.
Let represent the size of the mass attached to the spring. By Newton's Second Law, the net force on the mass at time
would be:
,
Since it is assumed that the mass here moves on a horizontal frictionless surface, only the spring could supply the net force on the mass. Therefore, the force that the spring exerts on the mass will be equal to the net force on the mass. If the spring satisfies Hooke's Law, then the spring constant will be equal to:
.
Since , it can be concluded that:
.
For the first mass , if the time period is
, then the spring constant would be:
.
Similarly, for the second mass , if the time period is
, then the spring constant would be:
.
Since the two springs are the same, the two spring constants should be equal to each other. That is:
.
Simplify to obtain:
.
At 10 m/s, it will take
(2 m)/(10 m/s) = 0.2 s
to bridge the gap.
_____
However, it will take an additional 0.514 seconds (0.714 s total) for the policeman to land on the building below. The answer depends on the meaning of the question.
(2 m)/(10 m/s) = 0.2 s
to bridge the gap.
_____
However, it will take an additional 0.514 seconds (0.714 s total) for the policeman to land on the building below. The answer depends on the meaning of the question.