Aladder is leaning against a vertical wall, and both ends of the ladder are at the point of slipping. the coefficient of friction between the ladder and the horizontal surface is =0.115μ1=0.115 and the coefficient of friction between the ladder and the wall is =0.253μ1=0.253 .

13.1 degrees

Explanation:

Let N be the normal reaction of the floor on the ladder

Let R be the normal reaction of the wall on the ladder.

Let W be the weight of the (assumed uniform) ladder.

Let L be the length of the ladder

Summing horizontal forces to zero

0.115N = R

N = R / 0.115

Summing vertical forces to zero

N + 0.253 R = W

R / 0.115 + 0.253R = W

Sum moments about the floor contact to zero

W[(L/2)sinθ] - R[Lcosθ] - 0.253R[Lsinθ] = 0

Divide all terms by L and sub for W

(R / 0.115 + 0.253R)[(1/2)sinθ] - R[cosθ] - 0.253R[sinθ] = 0

expand

(Rsinθ / (2)0.115 + (0.253Rsinθ)/2) - R[cosθ] - 0.253R[sinθ] = 0

Divide all terms by R and combine

sinθ / 0.23 + 0.1265sinθ - cosθ - 0.253sinθ = 0

sinθ / 0.23 + 0.1265sinθ - 0.253sinθ = cosθ

4.2393sinθ = cosθ

tanθ = 1 / 4.2393

θ = 13.3 degrees

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form