Answer:
The length of the load arm is 3 m
The length of the effort arm is 15 m
Spoons and scissors are class 1 levers
Explanation:
The data given in the force diagram of the lever (machine) are;
The length of the lever = 18 m = (Length of effort arm) + (Length of load arm)
The force applied at the effort = 100 N
The load lifted by the lever = 500 N
The mechanical advantage, MA is given as follows;
MA = Load/Effort = (Length of effort arm)/(Length of load arm)
∴ MA = 500 N/(100 N) = 5
Let 'x' represent the length of the effort arm, and let 'y', represent the length of the load arm, we have;
x + y = 18...(1) (given)
MA = 5 = x/y
∴ x = 5·y...(2)
Substituting the value of 'x' in equation (1) with x = 5·y gives;
x + y = 5·y + y = 6·y = 18
∴ y = 18/6 = 3
y = 3
The length of the load arm, y = 3 m
x = 5·y = 5 × 3 = 15
x = 15
The length of the effort arm, x = 15 m
When lifting food with a spoon, the fulcrum, which can be taken as the edge of the plate or the supporting finger, is in between bowl of the spoon and the point of application of the thumb towards the extremities of the spoon handle
Therefore a spoon is a class 1 lever
The pivot of a scissors is in between the item being cut (the load) and the holes where the finger applies an effort
Therefore, a scissors is a class 1 lever.
