02/05/2019 Speeding Up W Richards Worthing High School

Distance, Speed and Time 02/05/2019 Distance, Speed and Time D T S Speed = distance (in metres) time (in seconds) Dave walks 200 metres in 40 seconds. What is his speed? Laura covers 2km in 1,000 seconds. What is her speed? How long would it take to run 100 metres if you run at 10m/s? Steve travels at 50m/s for 20s. How far does he go? Susan drives her car at 85mph (about 40m/s). How long does it take her to drive 20km?

Balanced and unbalanced forces 02/05/2019 Reaction Consider a camel standing on a road. What forces are acting on it? These two forces would be equal – we say that they are BALANCED. The camel doesn’t move anywhere. Weight

Balanced and unbalanced forces 02/05/2019 Reaction What would happen if we took the road away? Weight

Balanced and unbalanced forces 02/05/2019 What would happen if we took the road away? The camel’s weight is no longer balanced by anything, so the camel falls downwards… Weight

Balanced and unbalanced forces 02/05/2019 What would happen if we took the road away? The camel’s weight is no longer balanced by anything, so the camel falls downwards…

Balanced and unbalanced forces 02/05/2019 1) This animal is either ________ or moving with _____ _____… 2) This animal is getting _________… 3) This animal is getting _______…. 4) This animal is…

Balanced and unbalanced forces 02/05/2019

Facts on Air Resistance 02/05/2019 Air Resistance is the force that acts ___________ anything that moves through the ______: It gets _______ when you move faster: It can be reduced by using a more “__________” (aerodynamic) shape: Streamlining also works when travelling through _______: Words – water, air, larger, against, streamlined

Words – increase, small, constant, balance Terminal Velocity 02/05/2019 Consider a skydiver: At the start of his jump the air resistance is _______ so he _______ downwards. 2) As his speed increases his air resistance will _______ 3) Eventually the air resistance will be big enough to _______ the skydiver’s weight. At this point the forces are balanced so his speed becomes ________ - this is called TERMINAL VELOCITY Words – increase, small, constant, balance

Words – slowing down, decrease, increases, terminal velocity, weight 02/05/2019 Consider a skydiver: 4) When he opens his parachute the air resistance suddenly ________, causing him to start _____ ____. 5) Because he is slowing down his air resistance will _______ again until it balances his _________. The skydiver has now reached a new, lower ________ _______. Words – slowing down, decrease, increases, terminal velocity, weight

Velocity-time graph for terminal velocity… 02/05/2019 Parachute opens – diver slows down Velocity Speed increases… Terminal velocity reached… On the Moon Diver hits the ground New, lower terminal velocity reached Time