Home L.C. Physics L.C. Physics Revision J.C. Physics J.C. Biology J.C. Chemistry Applied Maths Contact

Junior Cert: Force, Work and Power

Define and give the units for work, energy and power
State the relationship between work and power, and perform simple calculations based on this relationship
OP 4
Understand the concept of force
  Who knew concussion was an example of Newton's first law of motion YouTube. 4 mins  
  Explain it to me: Concussions link YouTube. 3 mins  
Recall that the newton is the unit of force      
Describe forces and their effects      
OP 5
  Microscopic simulation Friction between two rough surfaces, from absorblearning.com
4 Star
    And from a smooth surface 3 Star
    The effect of ball-bearings in reducing friction 4 Star
    The effect of lubrication in reducing friction 4 Star
  Rub the two books against each other and note the temperature
3 Star
  Nice counter-intuitive demonstration Interweave the pages from two books and then try to pull them apart. Youtube. 2 mins
4 Star
    How about using military tanks to pull them apart? Mythbusters on YouTube. 6 mins 4 Star
    Can this friction force lift a car? Vsauce find out on YouTube. 6 mins 4 Star
  Interactive simulation Set the coefficient of friction and then give the book a shove
3 Star
  You do know what happens when friction disappears Car pile-up caused by ice. Youtube. 5 mins. 3 Star
  Did you know that the primary function of saliva is to act as a lubricant? Take the cream-cracker challenge to find out more. 7 minutes from YouTube, but more fun to try it in class yourself.
4 Star
  Forces always act in pairs, and if one object pushes or pulls on another object, the force on both will be the same. This actually seems very strange - watch this YouTube clip and follow the instructions in relation to predicting in advance. 1 min. 5 Star
OP 6

Investigate the relationship between the extension of a spring and the applied force

  Excellent overview on why we have graphs Includes advice on drawing best-fit lines. Powerpoint 4 Star
  Demonstrating the mandatory expt YouTube 3 mins 3 Star
  An interactive Force-Extension graph for a piece of elastic From absorblearning.com
4 Star
  Simulation of the experiment. Attach different weights and measure the extension. From Phet.com
5 Star
  Simpler simulation, but less realistic From absorblearning.com
4 Star
OP 7
Weight is the force of gravity and weight varies with location      
  World's Roundest Object! Redefining The Kilogram YouTube. 12 mins. Brilliant, but a bit advance for first years. 5 Star
  Did you know that weight varies even around the Earth? To raise awareness, a Bavarian scale manufacturing company, is sending an acrylic garden gnome named Kern around the world, accompanied by a set of scales.
From New Scientist
4 Star
  Weightlessness and space Short video - Register or test-drive 5 Star
  Why are astronauts weightless? Short answer - they're not. YouTube 4 mins 4 Star
  Why doesn't the space shuttle fall to Earth? Cool explanation. youtube. one minute 5 Star
  Another viewpoint This time from an astronomer. Youtube. Two minutes 4 Star
  What's it like to experience weightlessness? An astronaut gives his experience. Youtube. 3 minutes 4 Star
How do they go the toilet? You know you want to know. Youtube. 2 minutes 4 Star
  Why zero-gravity bowling will never catch on link Cartoon 3 Star
  What happens when you wring a washcloth in space? Youtube. 3 minutes 5 Star
  Accelertion due to gravity      
  Which falls faster - a cannon-ball or a feather?
What about if you try it in a vacuum?
Place a vacuum jar over Galileo as he drops a canon-ball and feather from the leaning tower of Pisa 5 Star
  Brianiac try it as only they can link Youtube. 3 minutes 4 Star
  feather and hammer drop on the moon Youtube. 2 minutes. Poor quality 3 Star
OP 8

Mass in kilograms multiplied by 10 is approximately equal to weight in newtons on the surface of the earth

  When is a kilogram not a kilogram? Link Blogpost from thinkforyourself.ie  
  Famous documentary about Isaac Newton - he wasn't as wonderful a character as textbooks often make him out to be Link YouTube. 52 mins. Newton's Dark Secrets 5 Star