Please enable JavaScript.
Coggle requires JavaScript to display documents.
Laws of motion - Coggle Diagram
Laws of motion
Friction
Whenever a body moves or tends to move over the surface of another body, a force comes into play which acts parallel to the surface of contact and possess the relative motion
Static
The force of attraction which comes into play b/w two bodies before one body starts moving over the other body
Limiting
The maximum force of static friction which comes into play when a body just starts moving over the surface of another body
Laws of limiting friction
1) depends upon on the nature of the surfaces in contact and their state of polish
2) tangential to the two surfaces in contact and in a direction opposite to the direction of motion of the body
3) independent of the area of the surface in contact so long as the normal reaction remains the same
4) directly proportional to the normal reaction R between two surfaces
Kinetic
The force of friction which comes into play when a body is in a state of motion over the surface of another body
Angle of friction
Angle which the resultant of the limiting friction and normal reaction makes with the normal reaction
Angle of repose
Minimum angle that an inclined plane makes with the horizontal when a body placed on it just begins to slide down
-
-
-
Newton laws of motion
First law of motion
Every body continues in its state of rest or of uniform motion unless it is compelled by some external force to change that state
1) When a horse suddenly starts running, the rider falls backward
2) Dust is removed from a hanging carpet by beating it with a stick
3) when we shake the branch of a tree , its fruits and dry leaves fall down
Second law of motion
The rate of change of linear momentum of a body is directly proportional to the applied force and the change takes place in the direction of the applied force
Third law of motion
To every reaction, there is always an equal and opposite reaction
1) While walking, we press the ground with our feet slightly slanted in the backward direction
2) it is difficult to walk on a slippery ground or sand
3) While swimming, a person pushes water with his hands in the backward direction
-
-
Impulse
A large force acting for a short time to produce a finite change in momentum
1) force exerted by a bat while hitting a ball
2) blow of a hammer on a nail
3) force experienced by a person when he falls from a certain height on a marble floor
-
Applications of the concept of impulse
1) a cricket player lowers his hand while catching
2) automobile ( cars) are provided with shockers
3) a person falling from a certain height receives more injuries when he falls on a cemented floor than when he falls on a heep of sand
-
-
-
-
-
-
-
Full chapter formulas
1) p= mv
2) F = mv- mu ÷ t or F = dp÷ dt
3) impulse = F × t = m(v- u)
4) reaction = - action
5) 1) R = m(g+a)
2) R= m(g-a)
3) a=g , R = 0
4) R = mg
6) m1u1 +m2u2 = m1v1 + m2v2
7) recoil of gun , V = -mv ÷ M
8) resultant force of rocket
F= upthrust - weight of the rocket
F= u dm÷dt -mg
9) F1÷ sinx = F2÷ siny = F3 ÷ sinz
10) f1 +f2 +f3 = 0
11) coefficient of limiting friction = f max ÷ R
12) coefficient of kinetic friction = f k ÷ R
13) coefficient of friction = a ÷ g
14) F = coefficient of friction × mg cosa
15) W =mg ( sina - coefficient of friction cosa ) × S
16) W = ( a+ gsina + coefficient of friction cosa) × S
17) F = mv2÷ r
18) F = mass × centripital force