1. Science Camp (physics) Part one : motion analysis Presented by: Sam Lai and Li Man-long

2. What have we done? We have done two experiment: Experiment one : Free falling of basketball and rebound from the ground Experiment two : Releasing a ball from a slope

3. Experiment one : free falling of basketball and rebound from the ground Apparatus: 1 x basketball 2 x meter ruler 1 x digital camera

4. Experiment one Procedure: 1.The height of stage near playground was measured by meter rulers. 2. A basketball was released from the stage vertically. 3.The motion of free falling and rebound of the ball were recorded by the digital camera.

5. Experiment one Result : Height of the stage = 2.76m Time used for touching the ground = 0.74s Velocity of the ball when it reaches the ground = 7.252m/s K.E. of the ball before the impact = 26.7xmass J K.E. of the ball after the impact= 13.52xmass J

6. Experiment one Result : This is the acceleration-time graph of free falling of basketball and rebound from the ground. Displacement- time graph Velocity-time graph

7. Experiment one Conclusion : Air resistance can’t effect the result as the time of experiment taken is too short, because the ball travels with slow velocity. The acceleration of rebound of the ball changes sharply after impacting on the ground. Energy does not conserved by conservation of energy, therefore there is energy loss.

8. Experiment two : releasing a ball from a slope Apparatus: 1 x volleyball 2 x meter ruler 1 x digital camera

9. Experiment two Procedure: 1.The length of the slope outside school gate was measured by meter rulers. 2.A volleyball was released along the slope. 3.The motion of the ball was recorded by digital camera.

10. Experiment two Result : Length of the slope = 2.32m Initial velocity of ball = 0.4m/s Final velocity of ball = 3.25m/s Time taken for the experiment = 1.2s Hence, the acceleration of ball = 2.24m/s²

11. Experiment two Result : This is the velocity- time graph for releasing a ball from a slope. Acceleration-time graph

12. Experiment two Conclusion : The acceleration of ball must lesser than gsinθ because of overcoming the friction between ball and slope.