Core Practical Forces 2

• Aim 


  to investigate the effect of varying mass. on the acceleration of an object produced by a constant force
• Variables


  independent = mass, m

  dependent = acceleration, a

  control = force, f
• method

  1. Use the metre ruler to measure out intervals on the bench, e.g. every 0.2 m for a total distance of 1 m. Draw straight lines with pencil or chalk across the table at these intervals
  2. Attach the bench pulley to the end of the bench
  3. Put a 200 g mass on the car
  4. Tie some string to the toy car or trolley
  5. Pass the string over the pulley and attach the mass hanger to the other end of the string
• method 2

  1. Make sure the string is horizontal and is in line with the toy car or trolley
  2. Select a weight to put on the weight hanger that will gently accelerate the car along the bench. This provides the constant force on the car or trolley and will not change
  3. Hold the car at the start point
  4. Release the car at the same time as you or a partner start the stopwatch. the final time at 1.0 m
  5. Record the results in the table and repeat step 8 to calculate an average time for each interval
  6. Repeat steps 6-9 for increasing mass on the car, e.g. 400 g, 600 g, 800 g and 1000 g
• Result analysis


  use results to determine average spees between intervalsUse the distance between each interval (0.2 m) and the average time it takes for the toy car or trolley to travel that distance to calculate the average speed per interval

  
• result analysis 2

  • Compare the average speed between the first and last intervals for different weights
  • Use the equation below to calculate the acceleration between the first and the last intervals: