c) acceleration of free fall

bi) acceleration, g, of free fall

• acceleration of free fall (g) = 9.81ms^-2

to determine the acceleration of free fall using an electromagnet and a trap door

• an electromagnet holds a small steel ball over a trap door next to a metre rule

• the current in the circuit is switched off

  • the timer starts

  • the electromagnet demagnetises

  • the ball falls

• the ball hits the trap door

  • the electrical contact is broken

  • the timer stops

• calculate the acceleration using the time

  • s = ut + (½)at²

to determine the acceleration of free fall using light gates and a timer

• two light gates are connected to a timer, one above and one below the metre rule

• the ball is dropped

  • the ball passes the first light gate

  • the timer starts

  • the ball passes the second light gate

  • the timer stops

• calculate the acceleration using the time

  • s = ut + (½)at²