Sports Physics: Projectile Motion
Contents
Background Information 2
Equipment 3
Apparatus 3
Procedure 4
Variables 5
Results 6
Discussion 14
Conclusion 17
Bibliography 18
Appendix
Appendix 1 19
Appendix 2 21
Appendix 3 23
Appendix 4 25
Appendix 5 26
Appendix 6 28
Appendix 7 30
Appendix 8 31
Appendix 9 33
Appendix 10 35
Background Information
Sport relies on three major physics concepts: force, acceleration and velocity; many of which involve elastic propulsion and/or projectile motion. Various types of sporting equipment are constructed with springs and elastics, in order to absorb a force or apply a force to another object. In the context of this investigation, the spring is utilised to propel an object. According to Hooke’s law, F = -kx, the distance, x, that a spring is contracted or extended is proportional to the net force being exerted. Springs create a restoring force, so movement implies that potential energy is being converted to kinetic energy (BBC, 2014). Elastic potential energy is defined by Physics: A contextual Approach (2004) as “the energy stored in a compressed or expanded spring. It is proportional to the square of the distance which it is extended or compressed. The proportionality constant is equal to one half of the spring constant.” This can be expressed by the equation Ep = - ½ k x2, where Ep = elastic potential energy (J), k = spring constant (Nm-1) and x = extension or compression of the spring (m).
When an object, such as a ball, is propelled by a spring, the spring’s elastic potential energy is translated as the ball’s initial kinetic energy. This is due to the law of inertia, as the object will preserve their velocity and direction until acted upon by an unbalanced force. In the context of this investigation, the unbalanced force in action is gravity (Louviere, 2006). In fact, projectile motion is only dependent on gravitational acceleration (9.8 ms-2). When an object is released at the horizontal, inertia will carry it a short way
Background Information 2
Equipment 3
Apparatus 3
Procedure 4
Variables 5
Results 6
Discussion 14
Conclusion 17
Bibliography 18
Appendix
Appendix 1 19
Appendix 2 21
Appendix 3 23
Appendix 4 25
Appendix 5 26
Appendix 6 28
Appendix 7 30
Appendix 8 31
Appendix 9 33
Appendix 10 35
Background Information
Sport relies on three major physics concepts: force, acceleration and velocity; many of which involve elastic propulsion and/or projectile motion. Various types of sporting equipment are constructed with springs and elastics, in order to absorb a force or apply a force to another object. In the context of this investigation, the spring is utilised to propel an object. According to Hooke’s law, F = -kx, the distance, x, that a spring is contracted or extended is proportional to the net force being exerted. Springs create a restoring force, so movement implies that potential energy is being converted to kinetic energy (BBC, 2014). Elastic potential energy is defined by Physics: A contextual Approach (2004) as “the energy stored in a compressed or expanded spring. It is proportional to the square of the distance which it is extended or compressed. The proportionality constant is equal to one half of the spring constant.” This can be expressed by the equation Ep = - ½ k x2, where Ep = elastic potential energy (J), k = spring constant (Nm-1) and x = extension or compression of the spring (m).
When an object, such as a ball, is propelled by a spring, the spring’s elastic potential energy is translated as the ball’s initial kinetic energy. This is due to the law of inertia, as the object will preserve their velocity and direction until acted upon by an unbalanced force. In the context of this investigation, the unbalanced force in action is gravity (Louviere, 2006). In fact, projectile motion is only dependent on gravitational acceleration (9.8 ms-2). When an object is released at the horizontal, inertia will carry it a short way
Bibliography: BBC. (2014). Force and Elasticity. Retrieved March 7, 2014, from GCSE Bitesize: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/forces/forceselasticityrev1.shtml Brodie, R., & Swift, S Davis, D. (2002). Projectile Motion. Retrieved March 9, 2014, from Eastern Illinois University: http://www.ux1.eiu.edu/~cfadd/1150/03Vct2D/proj.html Department of Educationa dn Training Elert, G. (2014). Springs. Retrieved March 10, 2014, from The Physics Hpyertextbook: http://physics.info/springs/ Louviere, G Madden, D., Stelzer, T., Lindsay, I., Parsons, D., & Gaze, T. (2004). Physics: A Contextual Approach. Melbourne: Harcourt Education. The graph matched to a quadratic function produced the highest least spares regression value of R2 = 0.9726, therefore it represents the data more accurately than the logarithmic (R2 =0.8851), linear (R2 = 0.9716) and exponential functions (R2 =0.951).