Khoirul SolehahNur AthirahKhadijah

Sir Isaac Newton was born on 4 January 1643 . Sir Isaac Newton (4 January 1643 – 31 March 1727 [OS: 25 December 1642 – 20 March 1727])[1] was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian who is perceived and considered by a substantial number of scholars and the general public as one of the most influential men in history.

Who is he?

What can you predict?

Newton’s first laws

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Questions

Question 1:   The gravitational force of earth acting on a body of mass 1 kg is _______.

a)8.9 Nb)9.8Nc)980Nd)1NAnswer :bQuestion 2:   The momentum of a toy bus of 0.01 kg moving with a velocity of 5 m/s is 

a) 0.005 kg m/sb) 0.05 kg m/sc) 0.005 N sd) 0.5 kg m/s Answer : b

Question 3:   When an object undergoes acceleration

a) its speed always increasesb) its velocity always increasesc) it always falls towards the Earthd) a force always acts on it

 Answer : d

Question 4 :A force of 625 N acts on a body of mass 25 kg. Find the acceleration of the body.

Solution:Force (F) = 625 N  Mass (m) = 25 kgAcceleration (a) = ?F = ma  a= F/m            a= 625/25Acceleration = 25 m/s2

Question 5 :Calculate the change in momentum of a body weighing 10 kg when its velocity decreases from 20 m/s to 0.2 m/s.

Solution:Mass of the body (m) = 10 kgInitial velocity (u) = 20 m/s Final velocity (v)= 0.2 m/sChange in momentum = m (v-u) = 10 (0.2 - 20)= 10 (-19.8) Change in momentum = -198 N s

WHAT WOULD HAPPEN?

  Newton's 3rd law stated: "Forces always occur in pairs. If object A exerts a force F on object B, then object B exerts an equal and opposite force –F on object A" or in slogan style: 

"Every action has an equal and opposite reaction"

  In contrast, Newton's 3rd law always involves more than one object.    

• When a gun is fired, the force of the gas produced by burning gunpowder hurls out the bullet. By Newton's law, the gun itself recoils backwards. •  The nozzle of a big firehouse has handles which firefighters must grasp firmly, because as the jet of water shoots out of it, the hose itself is forcibly pushed back.       

LAUNCHING OF A ROCKET

OPEN THE BOTTLE

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THAT’S ALLTHANK YOU…(>_<)