# Determine the Acceleration of a Freely-Falling Object

Use three different methods to determine the acceleration of a freely-falling object

### Equipment

#### Method 1

The resource labelled ‘Researching free fall with an RBI timer’ allows you to do so by automatically plotting a table and ticker tape for you as follows:

1. Click on Launch. Timer and ticker tape are automatically engaged.

2. Electromagnet demagnetises causing steel ball to fall a distance, h, from the bottom of the ball to the top of the trap door o h is measured using a ruler

3. When the ball falls through the trap door is breaks the connection of the timer to the battery hence the timer stops

4. Record the time taken to fall h metres, t, repeat process three times, discard anomalies and find average t

5. Vary h and record corresponding t • Given that s = h, u = 0, a = g, t = t, using

6. Plot t2 against h, draw line of best fit, the gradient (m) will be 2/g .

#### Method 2

1. Attach a card to top of trolley/object and measure its width using a ruler

2. Release it from top of ramp and start the stopwatch

3. Light gate at the bottom of the ramp will record the time for which the card passes through

Calculate instantaneous final speed, v, of the card as:

4. Once the card reaches bottom of the ramp stop the stopwatch and record time taken, t

5. Repeat procedure 3 times, discard anomalies and calculate mean t

6. Vary v (by reducing distance of the trolley from bottom of ramp) and record the respective values of t

7. Given that u = 0, v= V, a = g, t = t,

v=u+at

v=gt

8. Plot v against t, draw line of best fit, the gradient (m) will be g

#### Method 3:

1. Clamp a thin piece of card to the top and measure height, h, from the centre of card to the top of the light gate using a ruler clamped parallel using a set square

2. Release the card from the top

3. Light gate at the bottom will record the time for which the card passes through

4. Calculate instantaneous final speed, v, of the card as:

5. Repeat procedure 3 times, discard anomalies and calculate mean v for the given h

6. Vary h and record the respective values of v

7. Given that s = h, u = 0, v= v a = g,

v2 =u2+2as

v2=2gs

8. Plot v2 against s, draw line of best fit, the gradient (m) will be 2g