Question

Question # 3

In the following figure, XY is a see - saw of 4 metres length. It is pivoted at its midpoint Z.
calculate the anticlockwise moment, about a horizontal axis passing through Z, of a child of weight
230 Newton who sits:

X. Z. Y


a. At X
b. 0.5 m from X
X
c. At Y
d. At Z and explain why it is acting that way​

Answer 1

Step-by-step explanation:

The moment of A about B is given by the formula

`M=Fd`

where M is the moment, F is the force acting perpandicular to the axis of rotation about B by A, and d is the horizontal distance of A from B along the axis of rotation.

Now

`F=230 (N)`

(a) At X,

`M=(230)(4/2)=460 (Nm)`

(b) At 0.5m from X,

`M=(230)(2-0.5)=345 (Nm)`

(c) At Y,

`M=-(230)(2)=-460 (Nm)`

where negative sign indicates clockwise rotation of the child about Z.

(d) At Z,

`M=(230)(0)=0 (Nm)`