2 Balanced & Unbalanced Forces Friday, April 21, 2017Balanced & Unbalanced ForcesTo be able to represent forces using arrows, and to understand the affects of balanced and unbalanced forces
3 Word searchUsing the word search, see if you can identify the key wordsStick your word search into your book!You have just five minutes, good luck!
4 Balanced forces - stationary / steady speed Push & Pull ForcesRemember, we use arrows to represent force - the bigger the force, the bigger the arrow isThe arrow points the way the force is actingThe arrows come in pairs, and if the force is balanced (not accelerating) the arrows will be the same size. If the force is unbalanced (accelerating) the arrows will be different lengths…Balanced forces - stationary / steady speedUnbalanced forces - acceleration
5 Car moving at a steady speed DemonstrationRemember a balanced force means there is no change in acceleration - so if an object is stationary, it will remain still, and if it was already moving, it will stay at that constant speedAn unbalanced force means there is a change in acceleration, in the direction of the greater forceCar stationary(balanced force)Car moving at a steady speed(balanced force)Car accelerating(unbalanced force)
6 Push & Pull ForcesHave a go at the worksheet - try and identify where the forces are, and represent them with an arrow - think about the arrows direction (up / down / pointing left / pointing right) and the arrows sizeSpring (Elastic Force) (pulling up)Weight (Gravity) (pushing down)
9 Balanced? What will happen if the cyclist pedals harder? If the cyclist pedals harder there will be an unbalanced force, and he will begin to accelerate in the direction he is cycling
10 Balanced? What will happen one team pulls harder than the other? How would you know if the teams were pulling with an equal force?If the two sides were pulling with an equal (balanced) force, then there would no be a change in their velocity (i.e. both teams would stay where they are)
11 Extra QuestionsMost pictures have more than one force affecting them (i.e gravity, reaction + push / pull forces)If the forces are the same (balanced) the object will stay still or remain at its original speed. If the forces are different (unbalanced) then the object will accelerate in that directionIn picture (b) - with the lady is pushing the shopping trolley with more force (4N), whilst the resistance is less (2N). This means the trolley is accelerating in the direction the lady is pushingThe length of the arrow is longer, because there is an unbalanced forceFriction is a force which slows objects down, e.g. drag, air resistance, the force used in brakes to stop objects