3-Aut2-E

Outcomes

• Pupils appreciate that force is a vector quantity and understand the nature of this.
• Pupils can name and label forces on stationary objects using arrows (1-D) and show that they are balanced.
• Pupils can add force vectors that act along a line.

Specification References

• 1.11 appreciate the vector nature of a force
• 1.12 add forces that act along a line

Main Body of Lesson

• In groups investigate vectors on the force tables. They can work through this Force Table Worksheet where they are asked to apply different arrangements of masses/forces pulling on a central block. They are asked to make and record a prediction before releasing the block and also to record their observations. The predictions should have been completed in the previous lesson.

EXTENSION - If there is time and you wish to extend to 2-D vectors a nice activity is to use the trio of ropes tied to a loop. In groups of four, have three pupils pull on the three ropes using forcemeters. They should pull and create a 'balanced loop' which is resting on the A3 paper. The fourth member uses a ruler to trace the three ropes with a pencil (on both sides) and label the force from the forcemeter. The centre of the loop should also be marked. Now have them take the loop and rope away and using the pencil draw the force vectors leading from the centre of the loop. The vectors should be in the correct direction and be drawn to scale. (i.e 2cm = 1N) Now using the acetate sheet they should trace the vectors one at a time 'adding them' head to tail. (They will get the direction correct if they concentrate on keeping the same acetate edge parallel with the same paper edge. The three force vectors should create a triangle showing that they are balanced or the resultant is zero.

Additional Information

Resources Required

• Class set of quantity cards in envelopes + whiteboards
• Class set of mini whiteboards
• Force tables - boards x 12, bull dog clips with one lever bent upward x 48 (or pulleys), string, block with four eyelets at the centre of each side, 100g mass sets, deep plastic trays x 24
• Extension activity only - Set of 'ring with three ropes' systems, 3 Newton meters x 3, A3 sheet x 1, acetate sheet x 1 , rulers x 1 and OHP pen x 1.

Safety/Hazards

Falling masses - watch feet,