A runner begins running at the beginning of 7th period and stops running at the end of the period. She runs at a pace of 10 km/h
1 answer:
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Answer:
Impulse = 88 kg m/s
Mass = 8.8 kg
Explanation:
<u>We are given a graph of Force vs. Time. Looking at the graph we can see that the Force acts approximately between the time interval from 1sec to 4sec. </u>
Newton's Second Law relates an object's acceleration as a function of both the object's mass and the applied net force on the object. It is expressed as:
Eqn. (1)
where
: is the Net Force in Newtons (
)
: is the mass (
)
: is the acceleration (
)
We also know that the acceleration is denoted by the velocity ( ) of an object as a function of time (
) with
Eqn. (2)
Now substituting Eqn. (2) into Eqn. (1) we have
Eqn. (3)
However since in Eqn. (3) the time-variable is present, as a result the left hand side (i.e. is in fact the Impulse
of the cart ), whilst the right hand side denotes the change in momentum of the cart, which by definition gives as the impulse. Also from the graph we can say that the Net Force is approximately ≈
and
(thus just before the cut-off time of the force acting).
Thus to find the Impulse we have:
So the impulse of the cart is
Then, we know that the cart is moving at . Plugging in the values in Eqn. (3) we have:
So the mass of the cart is .