A 65-kg swimmer pushes on the pool wall and accelerates at 6 m/s^2. The friction experienced by the swimmer is 100 N. How many N
1 answer:
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We can solve the problem by using the first law of thermodynamics:
where
is the variation of internal energy of the system
Q is the heat added to the system
W is the work done by the system
In this problem, the variation of internal energy of the system is
While the heat added to the system is
therefore, the work done by the system is
Answer:
The final angular speed is 0.223 rad/s
Explanation:
By the conservation of angular moment:
ΔL=0
L₁=L₂
L₁ is the initial angular moment
L₂ is the final angular moment
L₁ is given by:
As the door is at rest its angular moment is zero and the angular moment of mud can be considered as a point object, then:
where
r is the distance from the support point to the axis of rotation (the mud hits at the center of the door; r=0.5 m)
v is the speed
m is the mass of the mud
L₂ is given by:
ωf is the final angular speed
The moment of inertia of the door can be considered as a rectangular plate:
M is the mass of the door
W is the width of the door
The moment of inertia of the mud is:
Hence,