Which is the correct answer?
1 answer:
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Answer:
B) the change in momentum
Explanation:
Impulse is defined as the product between the force exerted on an object (F) and the contact time ()
Using Newton's second law (F = ma), we can rewrite the force as product of mass (m) and acceleration (a):
However, the acceleration is the ratio between the change in velocity () and the contact time (
):
, so the previous equation becomes
And by simplifying ,
which corresponds to the change in momentum of the object.
Jane's mechanical energy at any time is
where
is the potential energy, while 
is the kinetic energy.
Initially, Jane is on the ground, so the altitude is h=0 and the potential energy is zero: U=0. She's running with speed v, so she has kinetic energy only:
Then she grabs the vine, and when she reaches the maximum height h, her speed is zero: v=0, and so the kinetic energy becomes zero: K=0. So now her mechanical energy is just potential energy:
But E must be conserved, so the initial kinetic energy must be equal to the final potential energy:
from which we can find h, the maximum height Jane can reach:
where
Initially, Jane is on the ground, so the altitude is h=0 and the potential energy is zero: U=0. She's running with speed v, so she has kinetic energy only:
Then she grabs the vine, and when she reaches the maximum height h, her speed is zero: v=0, and so the kinetic energy becomes zero: K=0. So now her mechanical energy is just potential energy:
But E must be conserved, so the initial kinetic energy must be equal to the final potential energy:
from which we can find h, the maximum height Jane can reach: