Class II levers like ankles and wheelbarrows are useful because they provide mechanical advantage, by amplifying the input force
to provide a greater output force. In other words, we can lift a load without having to lift the full weight of the load. Prove using a mathematical relation that Class II levers provide mechanical advantage. You will need to use the rotational equilibrium condition. It will be helpful to draw a picture indicating the movement of the load. Also, to simplify we can assume the force is still perpendicular to by considering the case when the load just starts to move.
1 answer:
Answer:
The solution and the explanation are in the Explanation section.
Explanation:
According to the diagram that is in the attached image, the EFFORT force at point A and the load is at O point. The torque due to weight is:
TA = W * (a * cosθ)
The torque due to effort at C point is:
TC = E * (b * cosθ)
The net torque is equal to 0, we have:
Tnet = 0
W * (a * cosθ) - E * (b * cosθ) = 0
From the figure, you can observe that a/b < 1, thus E < W
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If I hold a positive charge in my hand and there are positive charges of equal magnitude 1 mm to your north and 1 mm to your east then the direction of the force on the charge I am holding is towards the north-east direction.
Reasoning:
It is given that there is a positive charge in my hand. There are two more positive charges with the same magnitude. One is 1 mm far towards the east, and the other one is 1 mm far towards the north. It is required to find the direction of the force acting on the charge in my hand.
Let the magnitude of the charge in my hand is Q, and the magnitude of the other charges is q.
Thus the electric force applied on the charge in my hand due to each other is,
Here k is the Coulomb constant, and r is the distance between the charges.
It is also known that the force on a positive charge due to another positive charge is acted outwards.
Thus, the force on the charge due to the charge on the east is,
And the force on the charge due to the charge on the north is,
As the forces are equal in magnitude and one is perpendicular to the other, thus the net force will be acted at an angle of from the north or from the north direction.
Thus the net force is acting in the north-east direction.
Learn more about the direction of the force here,
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