Work
Work is said to be done
Work is said to be done when the body moves in the direction of applied force
Define Energy
The capacity to do work
Define potential energy
The energy possessed by a body in a state of rest
Define kinetic energy
The energy possessed by a body in its state of motion
Define power
The rate of doing work
Factors affecting work
The magnitude of the force
The distance moved by the force
Name 5 forms of energy
Electric, Nuclear, Mechanical, Light, Chemical, Heat, Sound and Magnetic
What does potential energy depend on
Mass of the body
Height above the ground
What does kinetic energy depend on
The mass of the body
The speed of the body
Differentiate from energy
Any 2
SI unit is Watts(W)
Depends on time in which energy is spent
Power is the rate of doing work with the supplied energy
Conditions for work to be done
A force must act on the body
The force must change the position of the body
Give examples
a)Electric to light
b)Light to chemical
a) turning a light bulb on
b)photosynthesis
Expression for potential energy
U=mgh
Expression for Kinetic energy
KE=1/2MV^2
Differentiate from work
Any 2
The rate of doing work
SI unit is Watts(W)
Depends on time spent
30KGF of force is applied on a body and moves it by a distance of 0.4 Km
1KGF=10N
120,000
Define the law of conservation of energy
Energy can neither can neither be created nor destroyed but can change form
mass of A=10kg
Height=15m
mass of B=20kg
height=20m
Find out who has more potential energy
A=1500J
B=4000J
B
Who has more kinetic energy.
Body A=100g
Body B=0.2Kg
Body B
a) A force of 200N moves a body by a distance of 2m, find the work done
b) The time spent is 0.2 minutes
a)400J
4800W
30N acts on a body and moves it by 5m
150 Joules
Give examples of Kinetic to potential energy.(3)
Who has more potential energy
A=20KG
B=40KG
B
M=10kg
V=20m/s
2000J
A pump of 3kW is used for 20 seconds. How much work is done
60,000J