物理 2005 年 DSE、CE 選擇題

1.

Questions 1 and 2 : Patrick is driving along a straight horizontal road. At time $t = 0$ , he observes that an accident has happened. He then applies the brakes to stop his car with uniform deceleration. The graph shows the variation of the speed of the car with time.

Speed-time graph: constant 14 m/s until 0.8 s, then decreasing linearly to zero at 5.0 s

What is the reaction time of Patrick ?

2.

Questions 1 and 2 : Patrick is driving along a straight horizontal road. At time $t = 0$ , he observes that an accident has happened. He then applies the brakes to stop his car with uniform deceleration. The graph shows the variation of the speed of the car with time.

Find the distance travelled by the car from time $t = 0$ to $5.0$ s.

3.

A block remains at rest on a rough inclined plane. Which of the following diagrams shows all the forces acting on the block ? Note : $W$ = gravitational force acting on the block, $R$ = normal reaction exerted by the inclined plane on the block, and $F$ = friction acting on the block.

Four force diagrams A to D for the block

4.

A $1$ kg block is pulled by a horizontal force of $5$ N and moves with an acceleration of $2\ \mathrm{m\,s^{-2}}$ on a rough horizontal plane. Find the frictional force acting on the block.

Block on a rough horizontal plane pulled to the right by a 5 N force

5.

Weight-lifter lifting a barbell from the floor

The diagram shows a weight-lifter lifting a weight of mass $80$ kg from the floor to a height of $2$ m. Find the work done by the weight-lifter.

6.

Ferris wheel with eight cages and Edmund in the cage at the right, wheel rotating anticlockwise

The diagram shows Edmund riding the 'Ferris Wheel' in an amusement park. If the wheel is rotating at a uniform speed, which of the following physical quantities of Edmund would remain unchanged ?

7.

The photograph shows a hot potato wrapped by shiny aluminium foil. By what means can the foil help reducing the rate of energy lost from the potato to the surroundings ?

(1)conduction

(2)convection

(3)radiation

Photograph of a potato wrapped in shiny aluminium foil

8.

Figure (a): misty glasses; Figure (b): clear glasses

When Joanne gets off from an air-conditioned bus in the summer, her glasses become misty (see Figure (a)). After a while, the glasses become clear again (see Figure (b)). Which of the following physical processes are involved in the above phenomenon ?

9.

The diagram shows the image of a clock formed in a plane mirror. What is the time displayed by the clock at this instant ?

10.

Photograph of a girl reading small print with a magnifying glass

Cecilia uses a magnifying glass to read some small print. Which of the following diagrams shows how the image of the print is formed ?

Four ray diagrams A to D showing the image I of an object O formed by a lens