acceleration

• In the practical investigating the acceleration of an object, we vary the force to see how it affects the acceleration of an object of constant mass
• We also vary the mass of an object to see how it affects the acceleration produced by a constant force
• Equipment used:

  • Toy car attached to a piece of string
  • String looped around a pulley
  • Other end of the string attached to a 100 gram mass
  • Timer on the desk
  • Chalk lines drawn at equal intervals (e.g. every 10 centimeters)
• Procedure:

  • Hold the toy car at the starting point and let go
  • Record the time the car passes each distance marker
  • To accurately record time, use a mobile phone to video the experiment and play it back
• Repeat the experiment several times, decreasing the mass on the end of the string each time (e.g. 80g, 60g, 40g, 20g)

  • By decreasing the mass, the force acting on the toy car decreases
• In this experiment, the object consists of the toy car, the string, and the mass on the end of the string

  • When decreasing the mass on the end of the string, transfer that mass onto the toy car to keep the overall mass of the object constant
• Newton's second law of motion states that the acceleration of an object is proportional to the force applied

  • The force in this case is the weight of the mass on the end of the string
  • Therefore, the acceleration of the toy car should be proportional to the mass on the other end of the string
• Using the same equipment, we can investigate how varying the mass of the object affects the acceleration produced by a constant force

  • Keep the force constant (e.g. using a 100g mass on the end of the string)
  • Attach different masses to the toy car (e.g. 200g)
  • Newton's second law tells us that the acceleration of an object is inversely proportional to the mass of the object
  • Therefore, as we increase the mass of the toy car, the acceleration decreases