ICSE Physics Cheatsheet, Cheat Sheet of Physics

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.

I.M.P Question

Q1.Calculate the total moment acting on rod CD in S.I Unit. Given the forces are equal and parallel. C

50 N

D

50 N

10 cm 6 cm E

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

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.

(Not given in question) Ans- 60cm will be the centre of gravity for the metre ruler(as it balances without any weight being suspended) F 1 =20gf F 2 =50gf (not 50g) F 3

D

1 =10cm D 2 =50cm D 3 =30cm According to principle of moments in equilibrium; 20cm 50cm 60cm (^) 100cm ? (^) 20gf 50gf Question 2: – A metre ruler of weight 20gf, can be balanced at 60 cm mark, without any weight being suspended. It is pivoted at it’s centre and a mass of 50g is hung from one end. What minimum weight should be placed at 20cm mark to balance it. What is the mass of ruler at 40cm?

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:
• 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!