P2 2.2 Activity sheet Name:

Class:

Resultant forces Aim To develop your understanding of resultant forces and force diagrams. 1

A celebration cracker is pulled at each end until it tears open (Figure 1).

Figure 1 The pull forces are increased until the cracker rips open. Rewrite the following sentences filling in the blanks. a) The pull forces are always ……………. and opposite to each other as they increase. ........................................................................................................................................ ........................................................................................................................................ b) The cracker rips open because the pull forces on it are too ……………. for the paper. ........................................................................................................................................ ........................................................................................................................................ 2

Figure 2 shows a tug-of-war between the Blues and the Reds.

Figure 2 a) How much force does each team exert on the ground? Blues: .......................................................

Reds: ............................................................

b) What is the size and direction of the resultant force? ..................................................................................................................................................

AQA Science © Nelson Thornes Ltd 2006

P2 2.2

1

P2 2.2 Activity sheet Continued … 3

In each of the following examples, two forces, A and B, act on a ball along the same straight line through the centre of the ball. The forces act in the same direction as each other or in opposite directions. In each case: complete the force diagrams for examples 2–4 showing the two forces acting on the sphere. The force diagram for example 1 has already been completed. state the size and the direction of the resultant force on the object. Force A

Force B

1

12 N to the left

7 N to the right

2

7N to the right

12 N to the right

3

7N to the left

7 N to the right

4

12 N to the left

12 N to the left

AQA Science © Nelson Thornes Ltd 2006

Force diagram

Size and direction of the resultant force

P2 2.2

2