What type of energy system (open, closed or isolated) is represented by the picture and why?
1 answer:
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Answer:
to overcome the out of friction we must increase the angle of the plane
Explanation:
To answer this exercise, let's propose the solution of the problem, write Newton's second law. We define a coordinate system where the x axis is parallel to the plane and the other axis is perpendicular to the plane.
X axis
fr - Wₓ = m a (1)
Y axis
N- = 0
N = W_{y}
let's use trigonometry to find the components of the weight
sin θ = Wₓ / W
cos θ = W_{y} / W
Wₓ = W sin θ
W_{y} = W cos θ
the friction force has the formula
fr = μ N
fr = μ Wy
fr = μ mg cos θ
from equation 1
at the point where the force equals the maximum friction force
in this case the block is still still so a = 0
F = fr
F = (μ mg) cos θ
We can see that the quantities in parentheses with constants, so as the angle increases, the applied force must be less.
This is the force that balances the friction force, any force slightly greater than F initiates the movement.
Consequently, to overcome the out of friction we must increase the angle of the plane
the correct answer is to increase the angle of the plane
The canoe is moving at 14.1 m/s to the right after the collision.
Explanation:
According to the law of conservation of momentum, in absence of external forces the total momentum of the system must be conserved before and after the collision. So we can write:
where:
is the mass of the canoe
is the initial velocity of canoe (we take right as positive direction, and since the canoe is moving to the left, its velocity is negative)
is the final velocity of the canoe
is the mass of the raft
is the initial velocity of the raft
is the final velocity of the raft
Re-arranging the equation and substituting the values, we find: the final velocity of the canoe:
So, the canoe is moving at 14.1 m/s to the right after the collision.
Learn more about momentum:
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