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• Intermediate 1 Physics Movement Forces Speed and acceleration Moving bodies

Beath High School - Int 1 Physics

• Intermediate 1 Physics Movement Forces

Beath High School - Int 1 Physics

• Measuring forceThe unit of force is the n _ _ _ _ _ , symbol N.Forces can be measured using a n _ _ _ _ _balance.When a force acts on a spring balance, thespring inside it s _ _ _ _ _ _ _ _ . The position of the stretched spring on thes _ _ _ _ tells you the size of the force.n e w t o ns t r e t c h e ss c a l en e w t o n

Beath High School - Int 1 Physics

• WeightA newton balance is used to measuref _ _ _ _ .f o r c e_ _ newtons1 0

Beath High School - Int 1 Physics

• WeightWeight is a f _ _ _ _ .f o r c eWeight is the pull of the Earth on anobject due to g _ _ _ _ _ _ .A 1 kilogram mass (1 kg) has a w _ _ _ _ _of 10 newtons (10 N).This means the earth p _ _ _ _ the1 kilogram mass with a force of 10 newtons.g r a v i t yw e i g h tp u l l s

Beath High School - Int 1 Physics

• Calculating weightFor any object we can find its weight ifwe know the mass of the object inkilograms.weight = 10 x mass(N)(kg)

Beath High School - Int 1 Physics

• Calculating weightexample 1:Find the weight of a 2 kg bag of sugar.weight = 10 x mass = 10 x = N220The weight of a 2 kg bag of sugar is N20

Beath High School - Int 1 Physics

• Calculating weightexample 2:Find the weight of a 55 kg pupil.weight = 10 x mass = 10 x = 550 N55The weight of a 55 kg pupil is 550 N

Beath High School - Int 1 Physics

• FrictionFriction is a force that opposes the m _ _ _ _ _ of a body.m o t i o nThe force of friction can s _ _ _ a movingobject or s _ _ _ it down.s t o ps l o wThe force of friction can also keep objects fromstarting to m _ _ _ .m o v e

Beath High School - Int 1 Physics

• FrictionF _ _ _ _ _ _ _ is caused by the contact of twosurfaces.F r i c t i o nIf objects do not slide across each other easily,the force of friction between the surfaces oftwo objects is l _ _ _ _ .l a r g eIf the objects slide e _ _ _ _ _ , the force offriction is small.e a s i l y

Beath High School - Int 1 Physics

• FrictionWhen the force of friction between surfaces ish _ _ _ , we say they are rough, when the forceof friction is low, we say they are s _ _ _ _ _ . H _ _ _ FrictionSliding rough surfaces is like sliding the bristles of twobrushes - it is difficult. L _ _ FrictionSliding smooth surfaces islike sliding the backs of twobrushes - it is easy.h i g hH i g hL o ws m o o t h

Beath High School - Int 1 Physics

• Changing FrictionThe force of friction can be increased by making thesurfaces r _ _ _ _ _ _ or by pressing the surfacesh _ _ _ _ _ together.r o u g h e rh a r d e rThe force of friction can be reduced by making thesurfaces s _ _ _ _ _ _ _ or lifting the surfaces awayfrom each other.s m o o t h e rLubrication for example, uses o _ _ which lifts twosurfaces apart and r _ _ _ _ _ _ the force of friction.o i lr e d u c e sAir can also be used to lift surfaces aparte.g. in the h _ _ _ _ _ _ _ _ _ .h o v e r c r a f t

Beath High School - Int 1 Physics

• StreamliningWhen an object moves through the air, the air rubsagainst the object causing friction; this air friction iscalled air r _ _ _ _ _ _ _ _ _ .r e s i s t a n c eStreamlining is when you change the shape of the objectto r _ _ _ _ _ the air resistance.r e d u c eThe lines in wind tunnel testsshow the pattern of a _ _ flow.The smoother the air flow, thel _ _ _ the air resistance.The shape with the least air resistance is theteardrop shape - this is the m _ _ _ streamlined.a i rl e s sm o s t

Beath High School - Int 1 Physics

• Cars and StreamliningW _ _ _ tunnels are used to improve the streamlining ofcars.W i n dThe shape of a car can be made like a teardrop or like anaeroplane wing to r _ _ _ _ _ air resistance.r e d u c eSometimes a spoiler is fitted at the back to improve theair f _ _ _ making it more streamlined.f l o wAnother way to reduce air resistance is to make the carcloser to the g _ _ _ _ _ .g r o u n d

Beath High School - Int 1 Physics

• Balanced ForcesWhen two forces are the same size as each other andact on the same object but in directions, theybalance each other. The forces are called balancedforces.Some examples of balanced forces are;opposite

Beath High School - Int 1 Physics

• Balanced ForcesSome examples of balanced forces are;All of the objects shown above are acted on byb _ _ _ _ _ _ _ forces.b a l a n c e d

Beath High School - Int 1 Physics

• Examples of balanced forcesWhen two tug-of-warteams are pulling againsteach other but neither ismaking any progress, thef _ _ _ _ _ applied by eachteam must be balanced.f o r c e s

Beath High School - Int 1 Physics

• Examples of balanced forcesBefore skydivers open theirparachute they fall with a constantspeed called their t _ _ _ _ _ _ _velocity. This is because theirweight is balanced by thea _ _ r _ _ _ _ _ _ _ _ _ on theirbody.t e r m i n a la i rr e s i s t a n c e

Beath High School - Int 1 Physics

• Examples of balanced forcesWhen they open their parachutethey still fall at a constant speedbut much slower than beforebecause the air resistance isg _ _ _ _ _ _ with the parachuteopen. The air resistance is still e _ _ _ _to the weight so the forces are stillbalanced.e q u a lg r e a t e r

Beath High School - Int 1 Physics

• Examples of balanced forcesWhen a plane is travellingforwards, the air rushing overthe wings creates anu _ _ _ _ _ force.u p w a r dWhen the plane is flying level,this upward force balances thew _ _ _ _ _ of the plane.w e i g h tWhen the plane is taking off and landing, theupward and downward forces are n _ _ balanced.n o t

Beath High School - Int 1 Physics

• Intermediate 1 Physics MovementSpeed and acceleration

Beath High School - Int 1 Physics

• Measuring average speedWe can measure the average speed of any object bymeasuring the d _ _ _ _ _ _ _ it travels and the t _ _ _it takes to travel that distance.d i s t a n c et i m eAverage speeds are usually measured over l _ _ _ _distances or l _ _ _ times.l a r g el o n g

Beath High School - Int 1 Physics

• Measuring average speedThe average speed can then be found using the followingequation:Average speed =distancetime

Beath High School - Int 1 Physics

• Measuring average speedThe distance can be measured using a tape or m _ _ _ _stick.m e t r eTime is measured by a s _ _ _ _ _ _ _ _ or sometimes bya timer which starts and stops automatically.s t o p w a t c h

Beath High School - Int 1 Physics

• Measuring average speedAutomatic timers are oftenoperated by light g _ _ _ _ .g a t e sWhen a moving object cutsthe beam of light gate 1, thetimer s _ _ _ _ _ timing.s t a r t sWhen the moving object cuts the beam of light gate 2,the timer s _ _ _ _ timing.s t o p sIn this case,the average speed =distance between gatestime on timer

Beath High School - Int 1 Physics

• Examples on calculating speed1.A car travels a distance of 45 m in 30 s.Calculate its average speed.4530= 1.5 m/s

Beath High School - Int 1 Physics

• Examples on calculating speed2.A trolley passes through two light gates which are 2.5 metres apart.The timer measures a time of 15 seconds.What is the average speed of the trolley?2.515= 0.167 m/s

Beath High School - Int 1 Physics

• Examples on calculating speed3.A trolley passes through two light gates which are 1.2 metres apart.The timer measures a time of 0.8 seconds.What is the average speed of the trolley?1.20.8= 1.5 m/s

Beath High School - Int 1 Physics

• Instantaneous SpeedYour speed at any particular point during a journey iscalled the instantaneous speed - the speed at an instant.Calculating this speed is the same as calculating theaverage speed but the time interval must be very s _ _ _ _.s m a l l

Beath High School - Int 1 Physics

• Measuring Instantaneous SpeedBecause the time to be measured is so small, there is aproblem with r _ _ _ _ _ _ _ time (the time taken by aperson to start and stop a timer).r e a c t i o nTo measure the speed of a moving trolley, it is better touse a l _ _ _ _ g _ _ _ because there is no reaction time.l i g h t g a t eThe trolley is fitted with a card. The timer measures thet _ _ _ the card cuts off the beam of light.t i m e

Beath High School - Int 1 Physics

• Measuring Instantaneous SpeedIt s _ _ _ _ _ when the card cuts the light gate beam andit stops again when the beam is remade.s t a r t s

Beath High School - Int 1 Physics

• Measuring Instantaneous SpeedThe instantaneous speed is calculated using the length ofcard as the d _ _ _ _ _ _ _ and the timer reading as thetime, i.e.d i s t a n c e

Beath High School - Int 1 Physics

• Example on instantaneous speedA trolley is fitted with a card 0.10 m in length. The trolleyis set in motion and the card cuts a light gate. The time onthe timer is 0.025 seconds. Calculate the speed of thetrolley when it passes the light gate.= 4.0 m/s

Beath High School - Int 1 Physics

• AccelerationAcceleration is the change of speed of an object inone s _ _ _ _ _ .s e c o n dIf an object is getting f _ _ _ _ _ , it is accelerating the speed of the object is increasing.f a s t e rIf an object is getting s _ _ _ _ _ , it is decelerating the speed of the object is decreasing.s l o w e rDo not confuse acceleration with speed. A car can be travelling at a h _ _ _ speed but have zeroacceleration;h i g h also a car can have

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