Page 81 - text book form physics kssm 2020

Chapter 2 Force and Motion I

10. Photograph 2 shows the launching of a spacecraft using a rocket at a launch pad.

Photograph 2
(a) Explain how the release of hot gases through the rocket’s exhaust enables the rocket to
accelerate upwards.
(b) How can the acceleration of this rocket be increased?

11. Photograph 3 shows a hovercraft which can move
on land or on the surface of water swift ly because
of the support from a layer of air trapped under the
hovercraft . Th e hovercraft of mass of 25 000 kg
starts from rest and its engine produces a thrust, F
of 22 000 N.
(a) Determine the initial acceleration of the hovercraft
if there is no friction at that instant.
(b) What is the function of the layer of air trapped Photograph 3
under the hovercraft?

Enrichment Corner
Enrichment Corner

12. Kok Chew and Zulkefli wish to determine Earth’s gravitational acceleration. They plan
to release a table tennis ball from the third level of their school building. Discuss the
suitability of the table tennis ball in this experiment.

13. Assume that you are an engineer who is assigned to invent a model of fast train in
Malaysia. Th is train is required to travel at high speeds using levitation above the railway.
Draw your model of the fast train and list its properties by taking into consideration its
shape, materials, mechanism and safety aspects.

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