1) Work is defined as the product of the force acting on an object and the displacement of the object in the direction of the force. Positive work is when the force and displacement are in the same direction, negative work is when they are in opposite directions. 2) Kinetic energy is the energy an object possesses due to its motion. Common examples include the kinetic energy of moving air, water, and vehicles. Kinetic energy can be calculated as one-half the mass times the velocity squared. 3) For a body with mass m moving at velocity v, its linear momentum p is equal to mv. Its kinetic energy KE is equal to one-half mv squared. The relationship between linear momentum p and kinetic energy

3. θ
S

4. 1 eV = 1.6 ×10–19 J
1J = 107 erg
Work

5. POSITIVE
WORK
NEGATIVE
WORK
ZERO
WORK

7. F ( frictional force)
S (displacement)

8. θ = 90
T
S

10. So, Work Done during this small displacement
is dW =F.ds

11. C
D
A B

12. Xf Xi
ds
F. ds

20. H
dm
dm

22. ➔ Kinetic Energy
➔ Potential Energy
➔ Spring Energy

25. Moving Air (Wind)
possesses KE to
move windmills.
Flowing Water
possesses KE to
run water mills
Moving vehicle
possesses KE

26. Consider a body of mass m
moving with velocity v. Linear
momentum of the body, p = mv
Kinetic Energy of the body,
K.E= ½ . Mv^2
p = √2m Ek

27. K.E
p
M constant
parabola

29. This Photo by Unknown author is licensed under CC BY-SA.

31. Vibration of a simple
pendulum Vibrations of an elastic
string