It is because there is some air in the rubber tube and Bourdon gauge not included in V. (3)
2. To keep the syringe air tight. (1)
3. As the temperature should be kept constant, the gas is allowed to return to the room temperature after the air is expanded or compressed. (2)
4. To check whether there is significant air leakage during the action of piston. (May consider other answers, e.g., if the two readings of the volume are not consistent, the experiment should be repeated.) (2)
Total: 8 Overall:
Presentation and communication (2)
Total: 2
Full marks: 20
Marking Scheme−E1(P) page 2 of 2
Physics and CS(Physics) Sample SBA Task Practical Skills ( %)
Reporting ( %)
Total
Name :
E2 Newton’s second law of motion Class : No.:
Date :
Objective: To investigate the relation of the mass, acceleration and net force acting on an object.
Apparatus: data-logger interface with a motion sensor elastic threads (unstretched length about 20 cm) × 4 friction-compensated runway trolley 0.5 kg weights / additional trolleys × 3 electronic balance (optional if the mass of the trolley is known)
Part A—Net force and acceleration
Procedures:
1. Prepare a set-up to record the motion of a trolley on a runway as shown below. While necessary, adjust the runway for friction compensation.
2. Start data-logging. Use 1 elastic thread to pull the trolley along the track. The thread should be stretched by the same amount throughout.
3. From the slope of the velocity-time graph generated by the data-logging program, find the acceleration of the trolley.
4. Take one more confirmatory trial and obtain the mean value of the acceleration of the trolley.
5. Repeat steps 2–4 with 2, 3 and 4 elastic threads respectively. The threads should be stretched by