Linear momentum, sometimes simply call as momentum is the product of mass of the object and its velocity in the given direction. Linear momentum is a vector quantity and its direction will be same as the velocity of the object.

It can be formulated as-

G ⃗    =    mV ⃗

Fig. 7.1 shows the linear momentum of an object about a point O

Differentiation the above equation, we get-

(dG ⃗)/dx    =    m (dV ⃗)/dx
=    m a ⃗
(dG ⃗)/dx    =    ∑▒□(F ⃗ )
Or,
∑▒□(F ⃗ )    =    G ̇  ⃗

Where,
∑▒□(F ⃗ )= Resultant of forces. It can be calculated as-
Resultant Force,
∑▒□(F ⃗ )= ∑▒Fxi ̂ +∑▒Fyj ̂+ ∑▒Fzk ̂
= G ̇xi ̂ +G ̇yj ̂+ G ̇zk ̂
Or,
∑▒Fx = G ̇x
∑▒Fy= G ̇y
∑▒Fz= G ̇z

Note:
The S.I. unit of Linear Momentum is kg. m/s

Links of Previous Main Topic:-

• Introduction to statics
• Introduction to vector algebra
• Two dimensional force systems
• Introduction concept of equilibrium of rigid body
• Friction introduction
• Introduction about distributed forces
• Area moments of inertia in rectangular and polar coordinates
• Mass moment of inertia introduction
• Work done by force
• Kinematics of particles
• Position vector velocity and acceleration
• Plane kinematics of rigid bodies introduction
• Combined motion of translation and rotation
• Rectilinear motion in kinetics of particles
• Work and energy

Links of Next Mechanical Engineering Topics:-

• Linear impulse
• Conservation of linear momentum
• Direct collision of two bodies
• Oblique collision bodies
• Coefficient of restitution

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