forces by salah sari and doaa mahdawi
TRANSCRIPT
Conditions Of Equilibrium Of A Body
Done By : Doaa Al Mahdawi Salah Al Sary
وصلت إنحيا، البيت، إلى
القافية تص�ل كماخلل، بال
! : شكرا لنفسك قل شيئا توقعت إن
غدا حدسك،فاذهب وخانككنت، أين لترى
! : شكرا للفراشة وقلوردة إلى نظرت إن
توجعك أن دونبها، وفرحت
! : شكرا لقلبك قلاسمك� من حرفا تذكرت إن
بالدك، واسم ! طيبا ولدا كن
! : شكرا الرب لك يقول كي
محمود درويش
ForcesMain Objectives: •To define the Force.•To characterize the Force.•To distinguish between the different types of the Forces.•To deduce the conditions of equilibrium of two forces.
Definition of the Force:
A force is a mechanical action that may set a body in motion or modify its motion or modify its shape.
Pulling
Characteristics of Force:
•Its point of application: is the center of gravity of the body or point of contact.
•Its line of action: vertical, horizontal or oblique.
•Its direction: (upward- downward), (to the right, to the left), (upward to the right, downward to the right, upward to the left, downward to the left).
•Magnitude: Its numerical value in the SI unit Newton (N)
Measurement of Force:•A force is measured using spring balance.
•Its SI unit is Newton symbolized by N.
• A force is represented by force vector (convenient scale must be chosen to draw F).
Types of Force:
•Forces acting from a distance ex: magnetic force, electric force and gravitational force.
•Contact force ex: normal, pushing pulling, tension…
Particular Forces:
The weight:•The weight of a body is force acting from a distance
exerted by the earth on the object. It is also called the force of gravity.
The characteristics of weight:
•Its point of application: the center of gravity of the body.
•Its line of action: vertical.•Its direction: downward.•Magnitude: W = m × g.
Normal: It is a force exerted by a surface on a body. It is a contact force.
To find the characteristics of normal:
•Its point of application: point of contact.
•Its line of action: vertical
•Its direction: upward.
•Magnitude: ------
Tension: It is a force exerted by a spring or string on a body. It is a contact force.
To find the characteristics of tension:
•Its point of application: point of contact.
•Its line of action: vertical
•Its direction: upward
•Magnitude: T= k × ∆x
Force of friction: It is a force due to the sliding (motion) of a body. It is a contact force.
To find the characteristics of friction:
•Its point of application: point of contact.•Its line of action: along the line of motion.•Its direction: opposite to the motion.•Magnitude : -----
Equilibrium of a body:
Equilibrium of a body:
When a body is in equilibrium then the two forces have:
•Same line of action•Opposite direction•Same magnitude
Exercise I:
( S)
A box (S) of mass 1kg is suspended to the free end of a spring as shown in the figure.Take g=10N/Kg.
•Name the forces acting on solid (S).
•Calculate the weight of (S).
•Deduce the following characteristics of a force exerted by a spring on (S): a. Line of action . b. Direction . c. Magnitude .
DONE