4. (a) Which of these is a vector quantity? A mass B force C energy D distance (b) Figure 7 shows a ball bearing as it falls slowly through a clear, dense liquid - Edexcel - GCSE Physics Combined Science - Question 4 - 2021 - Paper 1

To determine the average speed of the ball bearing, follow these steps:

1. Apparatus:

   • Use a stopwatch (or a digital timer) to measure time.
   • A ruler or measuring tape to measure the distance.
   • A container filled with the clear dense liquid, possibly a test tube or similar apparatus.
   • Optional: Use a marker to indicate the starting and ending points on the container.

2. Measurements:

   • Measure a vertical distance between the marked points (top and bottom of the container).
   • Note the length as the distance the ball bearing will fall through.
   • Measure the time it takes for the ball bearing to fall from the top mark to the bottom mark using the stopwatch.

3. Calculation of Speed:

   • Use the formula: $ext{Speed} = \frac{ ext{Distance}}{ ext{Time}}$
   • Record the distance fallen and the time taken, then calculate the average speed of the ball bearing in the liquid.