Mechanics Ch7 -Ch11

Chapter 7-Conservation of Energy

Chapter 8- Linear momentum

The net work done by a conservative force on a particle moving around any
closed path is zero.

Principle of conservation of energy :K2+U2=K1+U1 image

The work done by a conservative force on a particle moving between two points
does not depend on the path taken by the particle.

Potential energy: U=-W.

Power

P=E/t

P=F.v

Escape velocity: sqrt(2GM/r)

Non-conservative, However, when the forces are taken into account, the total energy is still conserved.

Friction

Heat

Electrical energy

Chemical energy

Elastic potential energy= 1/2kx^2 Force exerted on the spring= -kx

Linear momentum,P=mv

Conservation of momentum

m1u1+m2u2=m1v1+m2v2

Total momentum does not change before and after

Law of conservation of momentum : When the net external force on a system of object =0, the total momentum of the system remains constant.

Impulse

Impulse=change in momentum

Impulse=mv-mu

The center of mass of a system of particles is the point that moves as though all of the system’s mass were concentrated there and all external forces were applied there. image

Rocket

Our system consists of the rocket and the exhaust
products released during interval dt. The system is closed and isolated, so the linear momentum of the system must be conserved during dt image

Collisions

Elastic collision image

Inelastic collision image

Chapter 9-Rotational Motion

For this chapter, the angles are measured in radians.

Angular velocity

Angular Acceleration

Frequency

Chapter 10-Angular momentum,L :Iw

If net torque = 0, the angular momentum does not change

w=v/R image

alpha=a/R image

Angular displacement

theta=wt image

T=1/f

Constant angular acceleration: image

Torque image

Chapter 11: Static equilibrium

Moment of inertia: image

Rotational kinetic energy: image

why a sphere that is rolling slowed down image

The total angular momentum of a rotating objects remains constant if the net external torque acting on it is zero.

Angular momentum is a vector quantity

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Condition of static equilibrium :image

Stability and balance

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Stress and strain:

Strain

Stress

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Fracture: image

Trusses and Bridges: image

Arches and Domes image