Un charpentier veut monter une poutre pour construire une charpente en haut d'une colline, il doit pour cela tirer la poutre sur la distance AB qui est une pente inclinée d'un angle de 15° AB = 30 mètres et la masse de la poutre est 60 Kg.
Durant la montée, la poutre es soumise a plusieurs forces dont son poids P. On rapelle que P=mg avec g=9.8 N/Kg. On définit le travail W d'une force F sur un déplacement rectiligne AB par W = F. AB ou W est en (J), F en Newton et Ab en mètres.
Calculer le travail du poids de la poutre sur la distance AB.

step-by-step explanation:

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116

statement #3: proof- ang is congruent to ang ecd : angles are congruent.  

step-by-step explanation:

1: the missing angles in statement #3  

a.) acb  

reason- the reason why the answer is acb is because angle ecd and angle acb are both the same size *that's what the word congruent means this is really simple.  

2: the missing word in reason #3  

c.) vertical  

reason- the reason why the answer is vertical is because the angles in that diagram on figure 2 is slanted, which is vertical, and the e and a both lay on vertical lines. along with the other's, but e and a are the 2 main points you want to focus on. and c is kind of like your starting point, because c is for both angles, not just one.  

i hope that was and understanding.