Mechanical Equilibrium Total forces = 0

N Suppose Tia weights 200 N How much is the tension on the string? 200 100 100

Equilibrium (Equal) N If all the forces acting on an object are balanced (equal to zero), the object is in equilibrium. There are two types of Equilibrium: Static and Dynamic

Name the forces here N Tension 1 Tension 2 Painter 1’s Weight Scaffold’s Weight Painter 2’s Weight means Painter 1’s weight + Scaffold’s weight + Painter 2’s weight - tension 1 - tension 2 = 0

For a scaffold in equilibrium Tension N Tension Painter’s Weight Scaffold’s Weight Painter’s Weight The sum of upward forces equals the sum of downward forces. ΣF = 0 and the scaffold is in equilibrium

N Try this one Draw the force diagram first. 150 N

N And another Draw the force diagram first. 450 N

N What is the tension? Hint: The man is in the center What is the weight of the man and the staging? 600 600 + 600 = 1200 N

If the painter moves to the right: Would decrease Would increase 400 N How would the tension in the ropes change? What is the total weight of painter and staging? 400 + 800 = 1200 N What is the net force? 1200N – 800 - 400 = 0 It is in static equilibrium 800 N

What is the tension in each string? 600 600 Total downward force = 1000 + 200 = 1200 N Since man is in the middle, this force is divided equally on both strings. 1200 ÷ 2 = 600 N each

What is Nisha’s weight if She stands on two bathroom scales and each scale reads 200 N? 200 N + 200 N = 400 N

N Another one Two vertical chains are used to hold up a 1000 N log. One chain has a tension of 400 N. What is the tension in the other chain? Log Weight - Tension 1 – Tension 2 = 0 1000N – 400 N – X = 0 600 N = X

Last one 1000 500 500 500 1000 If the crate and block move at constant speed, the tension in the string _______. This is ________ equilibrium 500

Work silently on worksheet Refer to today’s notes to complete this worksheet. Copying this worksheet will give you an “A” on this sheet and an “F” on the test. Next class we have a test on this chapter.