Analyze the pulley system shown in Figure 4, calculating its velocity ratio, the weight of the cement bag, its mechanical advantage, and its efficiency.

Given: Mass ($m$) = 50 kg.
Assume acceleration due to gravity ($g$) = $10 \text{ m/s}^2$.

Given: Load = 500 N (from part b), Effort = 300 N.

Given: Mechanical Advantage (MA) = 1.67, Velocity Ratio (VR) = 4.

Acceleration is the rate of change of velocity of an object. Its SI unit is meters per second squared ($\text{m/s}^2$).

If a body is moving with a constant velocity, its velocity is not changing. Therefore, its acceleration is zero.

To determine the acceleration of a moving body using a tape timer:

1. Setup: Set up an inclined plane (runway) at a gentle slope. Attach a ticker tape to a trolley and feed the tape through a ticker tape timer. Connect the timer to a suitable power supply (e.g., 12 V AC).
2. Procedure: Release the trolley from rest at the top of the inclined plane. As the trolley moves down, the ticker tape timer will make dots on the tape at regular time intervals (e.g., 50 dots per second, meaning each interval is $0.02 \text{ s}$).
3. Analysis:
   • Collect the ticker tape. Cut the tape into strips of equal time intervals (e.g., 10 dots per strip, which represents $10 \times 0.02 \text{ s} = 0.2 \text{ s}$).
   • Measure the length of each strip. The length of each strip is proportional to the average velocity of the trolley during that time interval.
   • Calculate the average velocity for each strip ($v = \text{length of strip} / \text{time interval}$).
   • Plot a graph of average velocity (y-axis) against the midpoint of the time interval for each strip (x-axis). The gradient of this velocity-time graph will give the acceleration of the trolley.