A football player carrying the ball runs straight ahead at the line of scrimmage and directly into a wall of defensive linemen.
1 answer:
solution:
Now the direction of this signed acceleration is towards in the direction of travel of the ball carrier.
But as this acceleration is negative we could just as validly state that the acceleration is
in the opposite direction to the ball carrier's travel.
Although both are valid, the latter statement is probably the answer you are expected to give .
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Answer:
The effective spring constant of the firing mechanism is 1808N/m.
Explanation:
First, we can use kinematics to obtain the initial velocity of the performer. Since we know the angle at which he was launched, the horizontal distance and the time in which it's traveled, we can calculate the speed by:
(This is correct because the horizontal motion has acceleration zero). Then:
Now, we can use energy to obtain the spring constant of the firing mechanism. By the conservation of mechanical energy, considering the instant in which the elastic band is at its maximum stretch as t=0, and the instant in which the performer flies free of the bands as final time, we have:
Then, plugging in the given values, we obtain:
Finally, the effective spring constant of the firing mechanism is 1808N/m.