Download ICSE Physics Cheatsheet and more Cheat Sheet Physics in PDF only on Docsity! ICSE PHYSICS IMPORTANT POINTS Created by Rajat Agarwal (I.C.S.E Board Physics Corrector) Trusted by the teachers of many schools! Guaranteed good score in physics! CHAPTER 1 : FORCE • The word ‘perpendicular distance’ is important in the definition of moment of force. Omission of the words in the definition, ‘perpendicular distance of the line of action of force from the axis of rotation’ will result in loss of marks. • Moment of force = Torque • For the definition of the moment of force better write – The turning effect of force (and not the body) on body that is pivoted about an axis. It is easier and smaller. According to Pythagoras theorem: CE = 8cm ∵ The two forces form a couple; Moment of couple = Either Force x Perpendicular distance between the two forces = 50 x 0.08m = 4 Nm - - (1) Note: The perpendicular distance here will be only 8 cm. It cannot be 6 cm as E is considered to be D. C 50 N D 50 N 10 cm 6 cm E 8cm • Learn examples of each type of equilibrium. The conditions for equilibrium are very important. • Static – Equilibrium at rest, Dynamic – Equilibrium at motion • Does the rain drop that is falling have a dynamic equilibrium ? The answer is Yes . It has a constant velocity • What is principle of moments ? – According to principle of moments in equilibrium (i.m.p), the sum of anticlockwise moments is equal to (never use symbols in definitions) the sum of clockwise moments about the same axis of rotation. Name one device based on it -(Beam Balance) • Two unequal forces act upon a body in opposite directions, but not in the same line. The net effect is : The body will experience both rotational and linear motion. • Never express negative moment of force with – ve sign. For e.g.. -15 Nm (wrong) 15 Nm (clockwise) – right Similar for + ve moment of force. • Mass = g or kg , Force = gf or kgf. • The ruler has mass unless it is specified. When we are asked to write the mass of ruler, write it in grams or kg only. And when we are asked to write force, write it in gf or kgf only. near the geometric centre of the body. • Learn centre of gravity for all objects thoroughly, one question will come. • In uniform linear motion(U.L.M), the speed and velocity remain constant. • In uniform circular motion(U.C.M), the speed remains constant but the velocity changes (as the direction changes) • Displacement of body in U.L.M can never be zero, while displacement of body in U.C.M can be zero. • U.C.M is accelerated motion and the acceleration is directed towards the centre of the motion. • Centripetal force direction – radially inward, centrifugal force – radially outward • The force necessary for rotation – centripetal force. For e.g. the electrostatic force of attraction is the centripetal force in the rotation of electrons around nucleus. • Centrifugal force is not the force of reaction of centripetal force. • Magnitude of centripetal: centrifugal = 1:1 • Centrifugal force- fictious force. • In U.C.M – velocity variable and acceleration variable. Created by Rajat Agarwal (I.C.S.E Board Physics Corrector) Trusted by the teachers of many schools! Guaranteed good score in physics!
