[EatRainbows]

I suck at mechanics.

A uniform ladder of mass 20 kg and length 5 m is standing on rough horizontal ground and leaning
against the top corner of a smooth vertical wall. The foot of the ladder is 2 m from the foot of the wall
and the point of contact between the ladder and the wall is 4 m from the foot of the ladder.

I have taken this to mean the ladder meets the top of the wall at 4m and 1m of the ladder goes over the wall. Firstly, is this right?

(a) Find the reaction between the wall and the ladder.

I have taken moments around the top and bottom of the ladder and get 71N (2sf) each time but the answer is 61.25N

(b) Find the normal reaction of the ground on the ladder

By resolving vertically you see that 20g=R but the answer is 165N =_=

Is the question just stupid or am I being stupid?

[Carolus]

I agree with the answers of 61.25N and 165N

You've described the situation correctly - have you drawn a diagram to see in which direction the forces are acting? In particular, which direction is the contact force between the ladder and the wall acting?

[EatRainbows]

(Original post by Carolus)
I agree with the answers of 61.25N and 165N

You've described the situation correctly - have you drawn a diagram to see in which direction the forces are acting? In particular, which direction is the contact force between the ladder and the wall acting?

Oh would it not be acting horizontally to the wall, would it be acting at an angle to the wall? Or perpendicular to the ladder?

[Carolus]

(Original post by EatRainbows)
perpendicular to the ladder?

Yep

[EatRainbows]

(Original post by Carolus)
Yep

Getting the right answers now, thank you very much