energy and work done

basic info

definition

S.I unit

others

types of energy

chemical potential energy

elastic potential energy

electrical energy

nuclear energy

sound energy

thermal energy

kinetic energy

gravitational potential energy

its is energy an object possess due to its motion and mass.

it is energy an object possesses because of its position in a gravitational field.

conversion of energy

light bulb turned on

work done

definition

S.I unit

formula

examples

sources of energy

non renewable

renewable

example questions + answers

releasing a bow

releasing a ball

it is the ability to do work.

energy is converted from one form to the other. Energy can be transferred.

joule (J)

energy cannot be created or destroyed

speed increase, KE increases

KE of an object is dependent on the speed the object is moving.

slower object, lesser KE

if two objects move at the same speed, the one with higher mass will possess more KE

height increase, GPE increases

stored in an objects height

depends on the weight of the object and the height it is at.

lower the positition, lesser the GPE

when two objects are at the same height, the heavier object will have higher GPE

electrical ➡ light + heat (energy)

car moves

chemical potential ➡ kinetic (energy)

archer releases arrow

elastic potential ➡ kinetic (energy)

power station -> 10000J electrical energy for light bulb to light up
-> 8000J light energy is converted from electrical energy
-> 2000J thermal energy is converted from electrical energy

the total amount of Joules would remain the same throughout

it is when a force acts on an object, and the object moves in the same direction as the force

Joule (J) (force done on object)

force x distance moved = work done

Marie lifts up a box

She applies a force of 40N on the box. The shelf is 2m above the floor

there is work done on the box because a force of 40N is applied to move the box. the box moves in the same direction which the force was exerted. (⬆) (force applied on box is up, direction the box moved was up)

lifting a box

marie holds a basket and stands without moving.

she applies a force of 50N on the basket, and holds it 1m above the floor

walks with a basket

she applies an upward force of 50N on the basket and walks while carrying the basket at the same height above the ground.

no work is done on the basket. A force of 50N is exerted on the basket but the basket does not move. (force exerted was up but basket no direction for no movement)

holding a basket

no work is done on the basket. a force of 50N is exerted on the basket but the direction of movement by the basket is not the same direction of force exerted on it. force applied was up but direction of basket was left/right

carrying a basket and walking

example 1

lifting a box notes

example 2

biofeuls

fossil fuels

they are the remains of the dead plants and animals and takes millions of years to form.

chemical potential -> heat -> kinetic -> electrical (energy)

it is burnt to be used, and it can be a fuel for cars, and more , but it produces harmful gases such as carbon dioxide and sulfur oxide when burnt

geothermal energy

hydroelectric energy

solar energy

wind energy

kinetic -> electrical (energy)

GPE -> kinetic -> electrical (energy)

heat -> kinetic -> electrical (energy)

light -> electrical (energy)