A car starts from rest at a stop light and reaches 20m/s in 3.5s. Determine the acceleration of the car
1 answer:
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We can solve the problem by requiring the equilibrium of the forces and the equilibrium of torques.
1) Equilibrium of forces:
where
is the weight of the person
is the weight of the scaffold
Re-arranging, we can write the equation as
(1)
2) Equilibrium of torques:
where 3 m and 2 m are the distances of the forces from the center of mass of the scaffold.
Using
and replacing T1 with (1), we find
from which we find
And then, substituting T2 into (1), we find
1) Equilibrium of forces:
where
Re-arranging, we can write the equation as
2) Equilibrium of torques:
where 3 m and 2 m are the distances of the forces from the center of mass of the scaffold.
Using
from which we find
And then, substituting T2 into (1), we find
Answer: 1.22 m
Explanation:
The equation of motion in this situation is:
(1)
Where:
is the final height of the ball
is the initial height of the ball
is the vertical component of the initial velocity (assuming the ball was thrown vertically and there is no horizontal velocity)
is the time at which the ball lands
is the acceleration due gravity
So, with these conditions the equation is rewritten as:
(2)
(3)
Finally: