Math Help Forum: Physics -equilibrium

How to solve this problem ?


Please answer in steps
Thank you

Hello mj.alawami

Originally Posted by mj.alawami

How to solve this problem ?


Please answer in steps
Thank you

The beam is m in length; it is uniform. So its weight acts m from each end.

If the reaction forces at A and B are and kg-wt respectively, take moments about A:

Solve this equation for .

Then resolve vertically (or take moments about B) to find .

Can you complete it now?

Grandad

Originally Posted by Grandad

Hello mj.alawamiThe beam is m in length; it is uniform. So its weight acts m from each end.

If the reaction forces at A and B are and kg-wt respectively, take moments about A:

Solve this equation for .

Then resolve vertically (or take moments about B) to find .



Can you complete it now?

Grandad

So is the answer RB=379N , and should i take into consideration the gravitational attraction or no?

Originally Posted by mj.alawami

So is the answer RB=379N , and should i take into consideration the gravitational attraction or no?

Hello mj.alawami

Originally Posted by mj.alawami

So is the answer RB=379N , and should i take into consideration the gravitational attraction or no?

If you are using Newtons as the unit of force, then, yes: multiply by , as skeeter has shown you. I was perhaps unwise to suggest a different unit (kg-wt or kg-force).

Grandad

Originally Posted by Grandad

Hello mj.alawamiIf you are using Newtons as the unit of force, then, yes: multiply by , as skeeter has shown you. I was perhaps unwise to suggest a different unit (kg-wt or kg-force).

Grandad

Will Ra and Rb have the same answer ?

Hello mj.alawami

Originally Posted by mj.alawami

Will Ra and Rb have the same answer ?

No. Let me re-phrase my first post, take the sum of the vertical forces and equate to zero:

(Some people denote this by .)

Substitute the value we've found for and solve for .

Grandad