Calculating Force

1
Calculating Force

• FMA
• Force equals Mass times Acceleration

2
Ski Story

• A speedboat pulls a 55-kg (121 lbs) water-skier.
  The force causes the skier to accelerate at 2.0
  m/s2. Calculate the net force that causes this
  acceleration.

3
Newtons 2nd Law

• F ma
• The net force on an object is equal to the mass
  of the object multiplied by its acceleration.

4
Units of Measure

• Force is measured in Newtons (N)
• 1 Newton is about the weight of an apple
• Mass is measured in Kilograms (kg)
• Acceleration is measured in meters per second per
  second (m/s/s)or per second squared m/s2

5
Simplifying the Ski Story

• Read and Understand
• What information are you given?
• Mass of water skier (m) 55 kg
• Acceleration of water-skier (a) 2.0 m/s2

6
Plan and Solve

• What quantity are you trying to calculate?
• The Net Force.
• Now, use the formula for Force (FMA)
• What was the mass? 55 kg.
• What was the acceleration? 2.0 m/s2
• F55 kg. 2.0 m/s2
• F 110 N (Newtons)

7
Practice

• Working out how much force is used to push a
  Formula1 car when it is broken down or has run
  out of fuel.
• If the car has a mass of 700 kg. and a driver
  pushes the car with an acceleration of 0.05m/s2
• ThenF MAForce 700kg x 0.05m/s2
• Force

8
More Practice

• The force at work on a Formula 1 car as it starts
  a race!
• If the F1 car has a Mass of 600kg and an
  Acceleration of 20m/s2
• Then we can work out the Force pushing the car by
  multiplying Mass by Acceleration like this
• 600kg x 20m/s2