Before starting this problem, review Conceptual Example 3 in your text. Suppose that the hail described there comes straight dow
1 answer:
Answer:
0.9 N
Explanation:
The force exerted on an object is related to its change in momentum by:
where
F is the force exerted
is the change in momentum
is the time interval
The change in momentum can be rewritten as
where
m is the mass
u is the initial velocity
v is the final velocity
So the formula can be rewritten as
In this problem we have:
is the mass rate
is the initial velocity
is the final velocity
Therefore, the force exerted by the hail on the roof is:
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Answer:
Total mechanical energy is the sum of potential energy plus kinetic energy. The kinetic energy will be 250 [J] and the potential energy is zero, therefore Total mechanical energy will be 250 + 0 =250[J]
Explanation:
This is a problem that applies the principle of energy conservation, i.e. mechanical energy that will be transformed into kinetic energy. We need to identify what kind of energy we have depending on the position of the ball with respect to the reference axis we take.
The reference axis or reference point is the point at which the potential energy is equal to zero, for this case we will take the ground as our reference point.
We know that the potential energy is defined by:
We can clear the mass from this equation:
When this body falls its potential energy will decrease but its kinetic energy will increase and reach its maximum value when the ball reaches the ground.
In such a way that its potential energy would be transformed into kinetic energy.
Since the potential energy has been transformed all into kinetic energy the amount of energy is conserved, therefore the total mechanical energy will remain the same.