Chapter 7 Dynamic1. The figure shows a moving trolley. A force is applied in the direction of its motion.

The application of the force will

A stop the moving trolleyB accelerate the moving trolleyC slow down the moving trolleyD change the direction of moving trolley

2. Which of the following are the effects of forces?

I Change the direction of the motionII Change the shape or size of an object

III Change the speed of the moving object

A I and IIB I and IIIC II and IIID I, II and III

3. The figure shows a wooden block is placed on an inclined plane. Which direction does the frictional force act on the wooden block?

Direction of force applied

Direction of moving trolley

C

A

B

D

Incline plane

Wooden block

4. The graph shown is plotted the extension of the spring against the force exerted on the spring.

What is the force exerted if the extension of the spring is 7 cm?

A 2.5NB 3.0NC 3.5ND 4.0N

5. The figure shows a boy is pushing a load.

What are the forces that influence the magnitude of the pushing force?

A Pulling force and gravitational forceB Frictional force and gravitational forceC Electrostatic force and magnetic forceD Gravitational force and electrostatic force

6. In a vacuum, a metal ball and a polystyrene ball will fall at the same time. Which of the following statements explain the situation?

A The metal ball lost its mass in a vacuumB Gravitational force are absent during the fallingC Frictional force exerted onto the balls are the sameD The metal ball and the polystyrene ball have the same mass.

Direction of pushing force

1 2 3 4 5 6

2

4

6

8Extension of the spring (cm)

Force (N)

7. The figure shows an extension of the spring is 6 cm when a load of 30 N is hanging to the spring.

What is the extension of the spring if the load is 20 N?

A 1.00 cmB 1.50 cmC 2.00 cmD 2.50 cm

8. The figure shows that a force of 500N is needed to move the metal block for 2m.

Calculate the amount of work done.

A 100 JB 1000 JC 100 kJD 1000 kJ

9. Which of the following statements show an advantage of frictional force?

A Produces heatB Produces soundC Wears out objectsD Allows a student to write

30 N

6 cm

20 N

Extension of the spring

2m

Metal block

500N

10. The figure shows a student weighing 50kg carries a load of 10 kg and climbs the steps in 20 seconds.

How much power is produced by the student?

A 60 wattsB 75 wattsC 90 wattsD 120 watts

1 Figure 1 shows the apparatus set up to investigate the extension of a spring. The result of the experiment is shown in Table 1.1.

FIGURE 1

Mass (g) Extension of spring (cm)

0 0

10 0.5

20 1.0

30 1.5

40 2.0

TABLE 1.1

4m

3m

5m50kg

10kg

(a) State the relationship between the mass of the load and the extension of the spring.

…………………………………………………………………………………………….[1 mark]

(b) Plot a graph to show the mass against the extension of the spring.

(c) What is the extension of the spring if the load is 60N?

…………………………………………………………………………………………….[1 mark]

(d) What is the conclusion of the experiment?

…………………………………………………………………………………………….[1 mark]

2 Figure 2 shows an experiment to study frictional force on different surface. Table 2.1 shows the reading of the experiment on the different types of surfaces.

Type of surfaces Reading of spring balance (N)

Smooth plank 5

Rough plank 7

On the marbles 2

On the pencils 2

Coated with grease 3

TABLE 2.1

(a) Mark the direction of frictional force in Figure 2[1 mark]

(b) Suggest a hypothesis for the experiment.

………………………………………………………………………………………....[1 mark]

(c) State one example where the frictional force is applied in our daily life.

….. …………………………………………………………………………………….[1 mark]

END OF QUESTION PAPER

Wooden blockWooden blockSpring balance

FIGURE 2

1B 6C2D 7C3D 8B4C 9D5B 10C

1 (a) the increase/higher the load the longer the extension of the spring (or vice versa) (b)

(c) 2.5cm (d) the increase/higher the load the longer the extension of the spring (or vice versa)

2 (a) Direction of Frictional force (b) The rougher the surface, the higher the frictional force (c) writing// walking//tyres (or any reasonable answer)