HS1 Physics MOTION IN A PLANE Chapter 3: Experiments

 

Experiment: Study of Motion in a Plane (Projectile Motion)

Objective:

To study the motion of a projectile and verify the independence of horizontal and vertical motions.

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Apparatus Required:

• Projectile launcher or a spring-loaded gun

• Ball (small metal or plastic)

• Carbon paper

• Measuring scale or tape

• Stopwatch (if needed)

• Protractor

• Plumb line

• White chart paper

• Stand with clamp

• Ticker timer (for motion tracking, optional)

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Theory:

Projectile motion is a form of motion in which an object moves in a curved path under the action of gravity. The horizontal and vertical motions are independent of each other, with:

• Horizontal motion at constant velocity.

• Vertical motion with constant acceleration due to gravity.

Equations of motion used:

• Horizontal: $x = u_x t$

• Vertical: $y = u_y t + \frac{1}{2} g t^2$

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Procedure:

1. Setup the apparatus on a level table. Place the launcher at the edge and align it horizontally.

2. Mount the chart paper on the floor below the edge of the table.

3. Place carbon paper on top of the chart to mark the point of landing.

4. Launch the projectile horizontally from a known height.

5. Measure the horizontal distance (range) from the base of the table to the point of impact.

6. Calculate the time of flight using the vertical height $h$ from which the projectile is launched:

   $$t = \sqrt{\frac{2h}{g}}$$

7. Calculate the horizontal velocity:

   $$u_x = \frac{Range}{Time}$$

8. Repeat the experiment 3–5 times to ensure accuracy.

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Observations:

Record height, range, time of flight, and calculate the theoretical and experimental velocities.

Trial	Height (h)	Range (x)	Time of Flight (t)	Velocity (u_x)
1
2
...

Result:

• The calculated values verify the independence of horizontal and vertical motions.

• Projectile follows a parabolic path, consistent with theoretical predictions.

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Precautions:

• Ensure the launcher is horizontal.

• Measure the height accurately using a plumb line.

• Use a flat and level surface for the experiment.

• Avoid air drafts.