Physics 2 A Lesson 7A Equal and opposite reactions AQA Additional Science

LO’s Recall terms action & reaction Recall unit of force © V Majer 2_1 Forces between objects14 September 2015 Velocity distance Speed Acceleration time m m/s m/s 2 s m/s Match the quantities with their units.

LO’s Recall terms action & reaction Recall unit of force 2_1 Forces between objects14 September 2015 Velocity distance Speed Acceleration time m/s m m/s m/s 2 s Match the quantities with their units. Isaac Newton explained how forces work. His name is remembered as the unit of force.

Additional Physics 2A Sections Speed, velocity Forces Work and and acceleration Energy © V Majer

Starter worksheet Summary questions Figure 1 Complete the sentences below. a)Speed (m/s) = b)The steeper a distance–time graph is, the greater the ………..…… it represents. c)The slope of a distance–time graph represents ………...……… d)In Figure 1 below: Line X represents …………... speed because the slope of the line is ………….… Line Y represents …………... speed because the slope of the line is …………... [Higher] a)Velocity is speed in a given ………...……… b)Acceleration is change of ………...……… per second. c)Acceleration (m/s2) = d)The slope of the line on a velocity–time graph represents …………...………. e)The area under the line on a velocity–time graph represents …………...……… f)The graph below represents the motion of an object that: started off at ………...……… speed, then accelerated at ………...……… acceleration, then moved at ………...……… acceleration, then decelerated at ………...…… deceleration Time Distance X Y Time Velocity 0 0

Video 79 Forces in action Questions How can you tell a force is acting? How are forces described? How are forces measured? What is a balanced force?

What is a force? A push or a pull May be unbalanced or balanced

What does a force do? Gives energy to an object Can set an object in motion, make it stop, or change its motion

Unbalanced forces change motion

Visit every station Record the forces using the Newton- meters provided Draw a sketch to show where and which forces are acting forces are acting Practical Circus Forces are measured in Newtons

A Newton-meter measures forces. Use the equipment to find the connection. Weight and mass Forces are measured in Newtons Mass (g)Weight (N) mass What does this column tell you about the connection? Be careful of any zero error – meter does not read zero with no force. What would a graph of mass vs weight look like?

Forces are represented by vectors

“For every action, there is an equal and opposite reaction.” Newton’s Third Law Or – Why would I get wet if I tried this?

skateboarder

For every action, there is an equal and opposite reaction The gases being expelled is the action. The rocket propelling forward is the reaction.

What have I learnt? The force on a ladder resting against a wall is …………….. and …………………to the force of the wall on the ladder A book is at rest on a table. The force of the book on the table ………….. The force of the table on the book is ………………. Copy and complete m3 equal opposite downwards upwards Use these words; Downwards equal opposite upwards

Forces are represented by vectors (size and direction) Copy

All Know that whenever 2 objects push or pull on each other they exert equal and opposite forces on each other Recall unit of force Most Be able to draw diagrams to demonstrate forces acting Be able to explain resultant force Some Be able to explain how friction makes a car move. Aims

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