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)

Gravity The 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

 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