Moments A Level Maths Exam Question

Matheen1

10

Can someone explain how I can get the answer for 12a?

Reply 1

old_engineer

11

Original post by Matheen1

Can someone explain how I can get the answer for 12a?

I would suggest:

* resolve vertically to find Td
* Let x represent the distance of the CoM of the beam from A
* Moments about C

Reply 2

Matheen1

OP

10

Original post by old_engineer

I would suggest:

* resolve vertically to find Td
* Let x represent the distance of the CoM of the beam from A
* Moments about C

Thanks did this to get x=1.2m but I need help with part b

Reply 3

old_engineer

11

Original post by Matheen1

Thanks did this to get x=1.2m but I need help with part b

Agree with x = 1.2m. For part b, you first need to work out the position on the beam of the new mass m. Then note that as the value of m is increased the tension Tc will decrease. The maximum allowable value of m will correspond to Tc = 0. More than that and the beam will tilt clockwise. Moments about D is the way to go.

Reply 4

Matheen1

OP

10

Original post by old_engineer

Agree with x = 1.2m. For part b, you first need to work out the position on the beam of the new mass m. Then note that as the value of m is increased the tension Tc will decrease. The maximum allowable value of m will correspond to Tc = 0. More than that and the beam will tilt clockwise. Moments about D is the way to go.