8.4 - free fall

Question 1

Does a heavier object fall faster than a lighter one

• explain

Answer 1

NO

• all objects fall at the same rate, under the constant acceleration due to gravity (g = 9.81)

Question 2

measuring the g

• method
• set up
• table of results
• graph
• the equation to calc g from graph

Answer 2

• set up apparatus as shown, the ball should be dropped
• take a multiflash photo/video of balls decent (stroboscope takes flashed at regular intervals), have a stopwatch and ruler visible in the background and record the results (as shown in table)
• plot a graph of s-t² (should be a straight line graph)
• using equation; s = ut + 0.5gt² , (u=0)

s = 0.5 gt²

y=mx+c

gradient, m = 0.5g

Question 3

state the symbol and constant for the acceleration of free fall

Answer 3

g

9.81 ms^-2

Question 4

give the 4 main SUVAT equations for an object in free fall

Answer 4

v=gt

v²=2gs

s=0.5gt²

s=(vt)/2

(u=0)

Question 5

measuring the g, reducing errors

• what is the main random error (+SI unit)
• how to reduce the effect of air resistance
• how to reduce the uncertainty of stopwatches

Answer 5

• measuring s, +-1mm
• use a heavy, smooth ball
• using a computer to automatically relece ball and time it