1. Equilibrium
Static Equilibrium

2. Static Equilibrium Examples
1. A hinge attached to a wall connects a 3.0 m long pole while the other end is held up by a rope as shown. If the tension in the rope is 250 N, and the force makes a 37° angle with the pole, what is the mass of the pole?
Hinge
3.0 m

3. Static Equilibrium Examples
1. A hinge attached to a wall connects a 3.0 m long pole while the other end is held up by a rope as shown. If the tension in the rope is 250 N, and the force makes a 37° angle with the pole, what is the mass of the pole?
Hinge
3.0 m

4. Static Equilibrium Examples
1. A hinge attached to a wall connects a 3.0 m long pole while the other end is held up by a rope as shown. If the tension in the rope is 250 N, and the force makes a 37° angle with the pole, what is the mass of the pole?
Hinge
3.0 m

5. Static Equilibrium Examples
2. A ladder whose length (l) is 15 m and whose mass m is 50. kg rests against a wall. The top of the ladder is a distance h = 11 m above the ground. The center of mass of the ladder is 1/3 of the way up. Assume that the wall, but not the ground is frictionless. What forces are exerted on the ladder by the wall and by the ground?

6. Static Equilibrium Examples
2. A ladder whose length (l) is 15 m and whose mass m is 50. kg rests against a wall. The top of the ladder is a distance h = 11 m above the ground. The center of mass of the ladder is 1/3 of the way up. Assume that the wall, but not the ground is frictionless. What forces are exerted on the ladder by the wall and by the ground?

7. Static Equilibrium Examples
2. A ladder whose length (l) is 15 m and whose mass m is 50. kg rests against a wall. The top of the ladder is a distance h = 11 m above the ground. The center of mass of the ladder is 1/3 of the way up. Assume that the wall, but not the ground is frictionless. What forces are exerted on the ladder by the wall and by the ground?
But

8. Static Equilibrium Examples
2. A ladder whose length (l) is 15 m and whose mass m is 50. kg rests against a wall. The top of the ladder is a distance h = 11 m above the ground. The center of mass of the ladder is 1/3 of the way up. Assume that the wall, but not the ground is frictionless. What forces are exerted on the ladder by the wall and by the ground?
But

9. Static Equilibrium Examples
2. A ladder whose length (l) is 15 m and whose mass m is 50. kg rests against a wall. The top of the ladder is a distance h = 11 m above the ground. The center of mass of the ladder is 1/3 of the way up. Assume that the wall, but not the ground is frictionless. What forces are exerted on the ladder by the wall and by the ground?
But

10. Static Equilibrium Examples
3. Four identical bricks, each of length L, are put on top of one another in such a way that part of each extends beyond the one beneath. Find, in terms of L, the maximum values of a1, a2, a3, a4, and h, such that the stack is in equilibrium.
The normal force acts from the edge of the brick below since at maximum a1 the top brick balances on the tip of the brick below.
Therefore, since the Fg acts from the center of gravity, the edge of the brick must be directly below the center of gravity so that FN exerts an equal but opposite torque as Fg.

11. Static Equilibrium Examples
3. Four identical bricks, each of length L, are put on top of one another in such a way that part of each extends beyond the one beneath. Find, in terms of L, the maximum values of a1, a2, a3, a4, and h, such that the stack is in equilibrium.

12. Static Equilibrium Examples
3. Four identical bricks, each of length L, are put on top of one another in such a way that part of each extends beyond the one beneath. Find, in terms of L, the maximum values of a1, a2, a3, a4, and h, such that the stack is in equilibrium.

13. Static Equilibrium Examples
3. Four identical bricks, each of length L, are put on top of one another in such a way that part of each extends beyond the one beneath. Find, in terms of L, the maximum values of a1, a2, a3, a4, and h, such that the stack is in equilibrium.

14. Static Equilibrium Examples
3. Four identical bricks, each of length L, are put on top of one another in such a way that part of each extends beyond the one beneath. Find, in terms of L, the maximum values of a1, a2, a3, a4, and h, such that the stack is in equilibrium.
Brick 1 is actually out beyond the edge of the table!