PHYSICS: FORMULAE
CHAPTER 1: FORCE
1. Moment of force = Force x perpendicular distance from the line of action
of force from the axis of rotation.
2. Couple = Either of the force x perpendicular distance between the two
forces or couple arm.
3. Principle of Moments = Sum of anticlockwise moments = Sum of
clockwise moments.
CHAPTER 2: WORK POWER ENERGY
1. Work = F x s Cos𝜃
2. Case i : if 𝜃 = 0°, the Work = F x S or m g h
3. Case ii : if 𝜃 = 90°, the Work = 0
4. Case iii : if 𝜃 = 180°, the Work = −F x S or − 𝑚 𝑔 ℎ
5. Relationship between joule and erg
1 joule = 1N x 1m = 10 dyne x 100 cm
= 10 𝑒𝑟𝑔
6. Power =
7.Relationship between S.I unit and C.G.S unit.
1 Watt = 1 J 𝑠 = 10 𝑒𝑟𝑔 𝑠
8. Energy = F X S Cos𝜃
9. Energy = Power x time
10. Power = =
, 11. Power = Force x velocity
12. Potential energy = m g h
13. Kinetic energy = 𝑚𝑣
14. 𝑝 = 2 𝑚 𝐾
(p – momentum, K is kinetic energy, m-mass of the object)
15. W = 𝑚𝑣 − 𝑚𝑢
16. 1eV = 1.6 x10 𝐽
17. 1 KWh = 3.6 x 10 𝐽
18. 1 H.P = 746 W
CHAPTER 3: MACHINES
1. Mechanical Advantage =
2. Velocity Ratio = =
3. Efficiency 𝜂 = 𝑥 100 %
.
4. Efficiency 𝜂 =
.
5. Mechanical Advantage of lever =
6. Principle of Lever = Load x load arm = effort x effort arm
CHAPTER 4: REFRACTION OF LIGHT AT PLANE SURFACES
1. = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (𝜇) where 𝜇 is the refractive index of second medium
with respect to first medium.
( )
2. 𝜇 =
( )
3. Relationship between wavelength in the two medium
𝜆, = where 𝜆, is the wavelength of light in a medium
CHAPTER 1: FORCE
1. Moment of force = Force x perpendicular distance from the line of action
of force from the axis of rotation.
2. Couple = Either of the force x perpendicular distance between the two
forces or couple arm.
3. Principle of Moments = Sum of anticlockwise moments = Sum of
clockwise moments.
CHAPTER 2: WORK POWER ENERGY
1. Work = F x s Cos𝜃
2. Case i : if 𝜃 = 0°, the Work = F x S or m g h
3. Case ii : if 𝜃 = 90°, the Work = 0
4. Case iii : if 𝜃 = 180°, the Work = −F x S or − 𝑚 𝑔 ℎ
5. Relationship between joule and erg
1 joule = 1N x 1m = 10 dyne x 100 cm
= 10 𝑒𝑟𝑔
6. Power =
7.Relationship between S.I unit and C.G.S unit.
1 Watt = 1 J 𝑠 = 10 𝑒𝑟𝑔 𝑠
8. Energy = F X S Cos𝜃
9. Energy = Power x time
10. Power = =
, 11. Power = Force x velocity
12. Potential energy = m g h
13. Kinetic energy = 𝑚𝑣
14. 𝑝 = 2 𝑚 𝐾
(p – momentum, K is kinetic energy, m-mass of the object)
15. W = 𝑚𝑣 − 𝑚𝑢
16. 1eV = 1.6 x10 𝐽
17. 1 KWh = 3.6 x 10 𝐽
18. 1 H.P = 746 W
CHAPTER 3: MACHINES
1. Mechanical Advantage =
2. Velocity Ratio = =
3. Efficiency 𝜂 = 𝑥 100 %
.
4. Efficiency 𝜂 =
.
5. Mechanical Advantage of lever =
6. Principle of Lever = Load x load arm = effort x effort arm
CHAPTER 4: REFRACTION OF LIGHT AT PLANE SURFACES
1. = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 (𝜇) where 𝜇 is the refractive index of second medium
with respect to first medium.
( )
2. 𝜇 =
( )
3. Relationship between wavelength in the two medium
𝜆, = where 𝜆, is the wavelength of light in a medium
