MECHANICS FLUID MECHANICS RIGID BODIES STATICS DEFORMABLE BODIES
MECHANICS FLUID MECHANICS RIGID BODIES STATICS DEFORMABLE BODIES DYNAMICS KINEMATICS KINETICS
Rigid Body Particle F 1 F 2 a F 2 b F 3 SFx=0 SFy=0 SM=0
FREE BODY DIAGRAM 1. Decide which part to be consider 2. Weight, W. Neglect or not? 3. External Force 4. Normal Reaction / Support Reaction
The mass The knot at C
30 o The uniform dresser has a weight of 360 N and rest on a tile floor which ms = 0. 25 1) Determine the smallest magnitude of force F needed to move the dresser. [ F = 121. 45 N] 2) If the man has a weight of 600 N, determine the smallest coefficient of static friction between his shoes and the floor so that he does not slip. [ ms = 0. 125]
(1) Determine the smallest magnitude of force F needed to move the dresser. (2)Determine the smallest coefficient of static friction between his shoes and the floor so that he does not slip.
FREE BODY DIAGRAM 1. Decide which part to be consider 2. Weight, W. Neglect or not? 3. External Force 4. Normal Reaction / Support Reaction
(1) Normal Reaction Forces normal to cross section, or surface N N = force of surface on beam
N
NA NB
1 NC NA NB Quiz 5 2
2)Support Reactions If a support prevents translation of a body in a given direction, then a force is developed on the body in that direction If rotation is prevented, a couple moment is exerted on the body
2)Support Reactions
2)Support Reactions
Ax Ay N
FREE BODY DIAGRAM 1. Decide which part to be consider 2. Weight, W. Neglect or not? 3. External Force 4. Normal Reaction / Support Reaction
Draw FBD 2 1 3
F sinθ F F θ θ F cosθ F sinθ
Example 1 Determine the tension in the cables AB and AD for equilibrium of the 250 [kg] engine shown in the figure.
solution 1. Draw FBD. Where? Engine weight = (250 kg) (9. 81 m/s 2) = 2. 452 [k. N] Tension cables AB and AD
solution 2. Equations of Equilibrium SFx = 0 SFy = 0 Ans
If we don’t know the direction of the force, just assume. y TB TD 300 2. 452 k. N Determine TB and TD x Quiz 2
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