Kinetic Energy

• Kinetic energy : total energy stored by an object in motion
• Kinetic energy : 0.5 x mass x velocity²
• A car has a mass of 1500kg and is travelling at a speed of 31m/s. How much kinetic energy is the car transferring?

  m = 1500

  v = 31

  KE = 0.5 x m x v²

  KE = 0.5 x 1500 x 31²

  KE = 720,750 J
• 1km = 1000m

  1 mile = 1600m

  1m = 100cm

  1m = 1000mm

  1cm = 10mm
• Kinetic energy and gravitational potential energy are : equal
• A 10kg ball is 1.5m off the ground. How fast is this ball travelling just before it hits the ground?

  GPE = 10 x 9.8 x 1.5 = 147

  GPE = KE

  147 = 0.5 x 10 x v²

  v² = 147/5 = 29.4

  v = 5.42m/s
• What assumption is made when calculating GPE and KE?

  That no energy is transferred

  to other forms
• Systematic error : The error that is caused by the way the experiment is set up.
• Random error : errors caused by things you cant control
• Zero error : Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero
• Accuracy : how close your measurement is to the real value