# Physics

posted by .

A uniform 250 N ladder rests against a perfectly smooth wall, making a 35 degree angle with the wall. (a) find the normal forces that the wall and the floor exert on the ladder. B) what is the friction force on the ladder at the floor?

• Physics -

Try to sketch a diagram as you read through this post. An image is worth a thousand words.

There are four forces acting on the ladder of length L and making θ=35 degrees with the vertical smooth wall and on a horizontal rough floor.

1. the weight W=250N acting downwards through the middle of the ladder
2. vertical reaction on the floor acting upwards, equal to W.

These two forces form a couple of magnitude
W(L/2)sinθ

3. Normal reaction N on the wall (horizontal) at the top end of the ladder, equal in magnitude to
4. Frictional force F acting horizontally at the bottom of the ladder.

These two forces form another couple equal to FLcosθ.

Since the ladder is in equilibrium, the two couples must be equal, thus

W(L/2)sinθ = FLcosθ
From which we can solve for F
= (W/2)tanθ
after cancelling L on each side and replacing sinθ/cosθ by tanθ.

• Physics -

so it would be 125 (tan 35) = 87.5 Awesome that is what it says in the back of the book THANK YOU!

• Physics -

Glad that it works out well!

• Physics -

In case you're still on, just want to let you know that I finish for the night. I can answer any question you may have tomorrow, unless another teacher is still on tonight.

## Similar Questions

1. ### physics

A uniform 250 N ladder rests against a perfectly smooth wall, making a 35 degree angle with the wall. (a)Draw a free body diagram of the ladder. (b) Find the normal forces that the wall and the floor exert on the ladder. (c) What is …
2. ### Physics

A uniform ladder 10.0m long and weighing 50.0N rests against a smooth vertical wall. If the ladder is just on the verge of slipping when it makes a 50 degree angle with the ground, find the coefficient of static friction between the …
3. ### Physics

A uniform ladder of length (L) and weight 100 N rests against a smooth vertical wall. The coefficient of static friction between the bottom of the ladder and the floor is 0.5. Find the minimum angle theta , which the ladder can make …
4. ### Physics

A ladder (L = 7.80 m) of weight WL = 360 N leans against a smooth vertical wall. The term "smooth" means that the wall can exert only a normal force directed perpendicular to the wall and cannot exert a frictional force parallel to …
5. ### Physics

An 8.5 m ladder whose weight is 310 N is placed against a smooth vertical wall. A person whose weight is 515 N stands on the ladder a distance 1.8 m up the ladder. The foot of the ladder rests on the floor 5.78 m from the wall. Calculate …
6. ### phsics

uniform ladder 25 ft long rests against a smooth vertical wall. The ladder weighs 15 Kg. The lower end of the ladder is 15 ft from the wall. A man weighing 80 Kg climbs up the ladder until he is 20 ft from the base of the ladder, (20 …
7. ### statics/physics

The uniform 10-kg ladder in the figure rests against the smooth wall at B, and the end A rests on the rough horizontal plane for which the coefficient of static friction is 0.3. determine the angle of inclination of the ladder and …
8. ### physics

A ladder (ℓL = 7.50 m) of weight WL = 350 N leans against a smooth vertical wall. The term "smooth" means that the wall can exert only a normal force directed perpendicular to the wall and cannot exert a frictional force parallel …
9. ### Physics

A uniform 160 N ladder rests against a perfectly smooth wall, making a 70 degree angle with the wall (ladder is 7 m long). (a) find the normal forces that the wall and the floor exert on the ladder. B) what is the friction force on …
10. ### physics

A ladder rests against a smooth wall (by smooth wall, we mean that the wall exerts in the ladder only a force that is perpendicular to the wall. There is no friction force). The ladder weighs 200N and its center of gravity is 0.4L …

More Similar Questions