Check the arithmetic.cracktheegg said:20N: 20*6 =60NM
Please show how you got to that number. Why negative?30N: -97.53Nm
By plugging in numbers too soon you introduced a rounding error. It should be exactly 80. Can you see an easy way to obtain that? And you lost the minus sign.40N: -40sin45 *2.83=80.04NM
Sign?10N: 10sin15(6)=15.6NM
cracktheegg said:20N has a moment of 20*0.06 = +1.2Nm
x component of force moment is -30cos(60° )*0.02
y component of force moment is +30sin(60° )*0.04
40N has a moment -40*0.02 = -80Nm
10N has a moment of -10sin(15°)*6
If it is in equilibrium,Anticlockwise moment should be equal to clockwise moment.cracktheegg said:There is question B, which ask what magnitude of the F will keep it equilibrium.
I get 27.48, but that's probably near enough.cracktheegg said:91.96= Fsin60 5.67-Fcos15
F= 91.96/ (sin60 5.67 -cos15)
=27.4N
correct?
Solving moment questions requires a systematic approach. First, draw a free body diagram and identify all the forces acting on the object. Then, choose a pivot point and apply the equations of equilibrium to solve for the unknown moments.
The equations of equilibrium are the sum of all forces in the x-direction equals 0, the sum of all forces in the y-direction equals 0, and the sum of all moments about a chosen pivot point equals 0.
A pivot point is a point on the object where the moments are being calculated. It is important to choose a pivot point that will make the calculations easier, such as a point where one or more forces pass through.
If you are unable to find a pivot point, you can choose any point on the object and apply the principle of moments. This states that the sum of clockwise moments equals the sum of counterclockwise moments.
Some common mistakes include not including all forces in the free body diagram, using incorrect units, and not considering the direction of the forces. It is important to double check your work and use a consistent set of units throughout the calculations.