MECHANICS

VELOCITY

V= d/t d-DISTANCE t-TIME

EXPRESSED IN (UNIT): m/s km/s miles/h km/h

VELOCITY OF LIGHT

3 x 10 E 8 m/s 3 x 10 E 5 km/s 3 x 10 E 10 cm/s 3x 10 E 11 mm/s 186,400 miles/s

AVERAGE VELOCITY

V=Vo + Vf/2

ACCELERATION

a=Vf-Vo/t

Expressed in ( m/s E 2)

GravityThe attraction

between two masses, such as the earth and

an object on its surface. Commonly referred to as the

acceleration of gravity.

                                  

    

GRAVITY

DOWNWARD ACCELERATION

9.81m/s E 2 on the Earth 1.6m/s E 2 on the Moon

Sir Isaac Newton

NEWTON’S LAW OF MOTION

I LAW---INERTIA II LAW---FORCE III LAW---ACTION/REACTION

I LAW

A BODY WILL REMAIN AT REST OR CONTINUE TO MOVE WITH A

CONSTANT VELOCITYIN A STRAIGHT LINE UNLESS ACTED

ON BY AN EXTERNAL FORCE

I LAW IN PRACTICE

II LAW

THE FORCE ( F) ACTED ON AN OBJECT WITH ACCELERATION (a) IS EQUAL TO THE MASS (m)

MULTIPLIED BY THE ACCELERATION

F=m * a

II LAW IN PRACTICE

III LAW

FOR EVERY ACTION THERE IS AN EQUAL AND OPPOSITE

REACTION

DIFFERENCE BETWEEN WEIGHT AND MASS

IS THERE ANY DIFFERENCE??

WEIGHT IS THE FORCE ON A BODY CAUSED BY THE

DOWNWARD PULL OF THE GRAVITY

WHO IS GOING TO FALL FASTER?

IN VACCUM ELEPHANT OR FEATHER ??

WITH THE AIR RESISTANCE!!!

WEIGHT IS EXPRESSED IN

NEWTONS NOT GRAMS OR KILOGRAMS

Wt = m * g

m –mass (kg) g – gravity ( m/s E 2)

GRAVITY

WITH GRAVITY OR WITHOUT?

MOMENTUM

P=m * v

TOTAL MOMENTUM BEFEORE INTERACTION IS EQUAL TOTAL

MOMENTUM AFTER INTERACTION

WORK

WORK = F * d F- FORCE (N) D- DISTANCE (m) EXPRESSED IN

JOULES (J)

POWER

P=WORK/TIME

EXPRESSED IN WATTS (W)

ENERGY IS THE ABILITY TO DO WORK

POTENTIAL ENERGY

PE = m * g * h m- mass (g) g- gravity ( m/s E 2) h- height (m)

KINETIC ENERGY

KE = ½ m * v E 2 m – mass (m) Velocity (m/s)

POTENTIAL & KINETIC

TRANSFER OF ENERGY

TRANSFER OF ENERGY ELECTRIC-THERMAL-KINETIC-ELECTROMAGNETIC

HEAT

IS THE KINETIC ENERGY OF THE RANDOM MOTION OF MOLECULES

HEAT TRANSFER

CONDUCTION

CONVECTION

RADIATION

CONDUCTION

TRANSFER OF HEAT BY TOUCH

CONVECTION

MECHANICAL TRANSFER

OF HOT MOLECULES IN A LIQUID OR GAS

RADIATION

TRANSFER OF ENERGY THROUGH SPACE

Temperature Scales

TEMEPERATURE CONVERSION

Tc = 5/9 ( F-32) Tf = (9/5 C) + 32 Tk = Tc + 273