- #1

trajan22

- 134

- 1

quick question,

A uniform, aluminum beam 9.00 m long, weighting 300 N, rests symmetrically on two supports 5.00 m apart. A boy weighing 600 N starts at point A and walks toward the right.

How far beyond point B can the boy walk before the beam tips?

ans=1.25 m

How far from the right end of the beam should support B be placed so that the boy can walk just to the end of the beam without causing it to tip?

this second part is the part I am stuck on.

my equations are

all of these are the sum of the forces in that direction

Fx=0

no forces are acting in this direction

Fy=(F(support A)+F(support B))-(F(gravity on bar)+F(gravity on boy))

force of gravity of bar is at its center of mass between the two blocks

Tz=(F(gravity on bar)*(distance)-F(gravity on boy)*(distance))

rotation point is set around point b

i was able to solve for the first part of this problem however for the second part it appears that i have 2 unknowns with 1 effective equation so I am not really sure how to go.

i have included a figure but chances are it will take some time for it to come up.

A uniform, aluminum beam 9.00 m long, weighting 300 N, rests symmetrically on two supports 5.00 m apart. A boy weighing 600 N starts at point A and walks toward the right.

How far beyond point B can the boy walk before the beam tips?

ans=1.25 m

How far from the right end of the beam should support B be placed so that the boy can walk just to the end of the beam without causing it to tip?

this second part is the part I am stuck on.

my equations are

all of these are the sum of the forces in that direction

Fx=0

no forces are acting in this direction

Fy=(F(support A)+F(support B))-(F(gravity on bar)+F(gravity on boy))

force of gravity of bar is at its center of mass between the two blocks

Tz=(F(gravity on bar)*(distance)-F(gravity on boy)*(distance))

rotation point is set around point b

i was able to solve for the first part of this problem however for the second part it appears that i have 2 unknowns with 1 effective equation so I am not really sure how to go.

i have included a figure but chances are it will take some time for it to come up.