science f2 chap 10 paper 2

Chapter 10 : SIMPLE MACHINE

PAPER 2

1 Figure 1 shows a wheelbarrow. (PMR 2005)

Figure 1.1

(a) On Figure 1.1, label the position of the fulcrum.(1 mark)

(b) (i) Based on Diagram 1.1, state the class of lever of the wheelbarrow.

______________________________________________________________(1 mark)

(ii) Give one reason for your answer in (b)(i).

____________________________________________________________ (1 mark)

(c) Based on Figure 1.2, choose one tool with the same class of lever as the wheelbarrow in Figure 1.1.

Mark ( ) in the box for the tool.

Fishing rod Nutcracker Pliers

Figure 1.2(1 mark)

Prepared by : Lau SC 2012


2.

(d) Figure 1.3 shows the situation when a force and a load are balanced.

Figure1.3

Calculate force P needed to balance the metre rule.

Use the following formula:

Load x Distance of load from fulcrum = Force x Distance of force from the fulcrum

_________________________________________________________ (2 marks)

Diagram 2.1 shows a pair of pliers. (PMR 2007)

Diagram 2.1

(a) (i) What is the class of lever of the pair of pliers?

_____________________________________________________________(1 mark)

(ii) State one reason for the answer in 2(a) (i).

_____________________________________________________________(1 mark)



(b) Based on Diagram 2.1, why is it easier to cut the wire when we hold the pliers at K rather than at L?

_______________________________________________________________ _______________________________________________________________

(1 mark)

(c) Diagram 2.2 shows a worker carrying a load using a wheel barrow.

Diagram 2.2 Draw a lever system for the wheel barrow and label the position of load, force and fulcrum.

( 2 marks)

(d) Diagram 2.3 shows a system when a force and a load are balanced.

Force 50 N Load W

20 cm

Diagram 2.3

Calculate load W when the system is in equilibrium. Use the following formula :

W = _________________ N(2 marks)


Load x Distance of load from the = Force x Distance of force from the fulcrum fulcrum

80 cm


3.

(e) Diagram 2.4 shows two persons, P and Q, rowing their boats.

Figure 2.4

Why does P use less force than Q to row his boat?

_______________________________________________________________

_______________________________________________________________(1 mark)

(a) Diagram 3.1 shows four devices, P, Q, R and S that use the principle of lever. (PMR 2008)

Diagram 3.1

State one characteristic that can be observed from any three devices by referring to the positions of fulcrum, load and force.

Device Characteristic

(3 marks)


Metre rule


(b) Classify the devices, P, Q, R and S into two groups based on their common characteristics.

Common characteristics

Devices

(4 marks)

(c) Diagram 3.2 shows three situations, J, K and L, of a device using principle of lever.

Diagram 3.2Based on Diagram 3.2

(i) State one inference about the device.


P, Q, R, S


____________________________________________________________(1 mark)

(ii) Predict the force needed to lift the rock at L.

____________________________________________________________(1 mark)

(iii) State the relationship between the length of the crow-bar and the force needed to lift the rock.

____________________________________________________________(1 mark)

ANSWERS:

PMR 2005

1(a)

(b)

(c)

(d)

(i) Second class lever(ii) Load is between fulcrum and effort.

Nutcracker

40 x 20 = 100 x P 800 = 100P 8N = P

PMR 2007

2(a)

(b)

(c)

(d)

(i) First class lever(ii) The fulcrum is between the effort and load / The fulcrum is in the middle

The longer the distance of the effort from the fulcrum, the less effort is required.

Force / E

L / Load F / Fulcrum

W x 100 = 50 x 20 W = 10 N


fulcrum


(e) Distance of the applied force from the fulcrum is longer. / Distance of the load from the fulcrum is shorter.

PMR 2008

3(a)

(b)

(c)

Able to state one characteristic of any three devices.P : Load is between effort and fulcrum.Q : Effort is between load and fulcrum.R : Fulcrum is between effort and load.S : Fulcrum is between effort and load.

Common characteristics

Devices

(i) The length of the crow bar influences the force needed to lift the rock.(ii) 100 N(iii) The longer the length of the crow bar, the less force needed to lift the rock.


P, Q, R, S

The fulcrum is between the load and effort

The fulcrum is not between the load and effort

PliersScissors

Bottle openerIce tongs

science f2 chap 10 paper 2

Documents