1. ON THE MOVE MOMENTUM

2. These questions relate to our last area on force production. 1.State each of Newton’s three laws and demonstrate your understanding of each law by using a sporting example: 2.Using Newton’s second law of motion, explain why a medicine ball will not move as quickly as a basketball when they are both thrown with the same force: 3 Provide three examples of action and reaction forces in sport:

3. What does it take to lay the perfect tackle? You are going to discover that physics and mathematics play a role in making you the perfect tackler or making sure your team matches up correctly.

4. # Momentum is a measure of the amount of motion that an object has. # momentum = mass x velocity # Momentum is important when objects collide. Every time 2 objects there is a change in momentum. Both objects will continue in the same direction of the object with the greatest momentum

5. # If 2 objects have the same mass but different velocities, the object with the greater velocity will have the greater momentum # If 2 objects have the same velocity but different masses, the object with the greater mass will have the greatest momentum

6. 1.What 2 factors would determine an object’s momentum? 2.Which object would be harder to stop: a volleyball that has been set up ready to be spiked or a baseball that has been struck into the outfield? Justify your answer. 3.Using the picture on the first page describing momentum calculate the momentum of both players before the collision. Which player has the greatest momentum? How can the player with the less mass increase their momentum?

7.  How do divers, gymnasts and skaters control the speed of their rotations in the air?  Angular motion obeys the same principles as linear motion; however, they have a slightly different spin!  The amount of angular motion possessed by a body is known as the angular of momentum of an object.  The moment of inertia is the resistance of an object to changes in its angular motion.  Newton’s laws can also be transferred to angular motion

8.  Before we move on to Newton’s laws you may want to have an understanding of torque  Eccentric forces cause an objects to rotate and move forwards.  This effect is known as torque  Torque is the tendency of an object to rotate.  Torque will cause a gymnast to rotate around a bar.

9.  1 st LAW – The angular momentum of a body remains constant unless acted upon by an external torque  2 nd LAW – A torque applied to an object will produce a change in angular motion in the direction of the applied torque that is directly proportional size of the torque and inversely proportional to the moment of inertia of the object.  3 rd LAW – For every torque there is an equal and opposite torque.

10.  Moment of inertia = mass x radius(squared)

11. For an excellent example of angular momentum please visit the following youtube clip. http://www.youtube.com/watch?v=4SGGAWGGu3o

12.  When the main objective of a sport is to hit, kick or throw an object or ball as far as possible, it is important that it is released or struck with maximum velocity  By coordinating all of the body parts that are involved in the movement, athletes are able to generate maximum velocity of the hand during a throw, the foot during a kick and the club, racquet or bat during a hit. This is known as the summation of momentum.  Highly skilled performance is characterised by well-timed, coordinated movements that result in optimal velocity of the object at impact or release.

13.  Golf swings are a perfect example of the summation of momentum to produce the perfect hit.

14. 1.A gymnast performs three different somersault dismounts off a beam. In which position will the moment of inertia be the greatest and in which position will rotation be the fastest? * Pike * Tuck * Layout 2.Provide a sporting example that demonstrates the correct application of each of Newton’s three laws of angular motion. 3.How can the moment of inertia of a golf club be increased or decreased? Outline the advantages or disadvantages of selecting a longer club.

15. You can now go on with your biomechanics booklet or complete the attached practice test. TO THISFROM THIS