Energy concepts

Learning objectives To know how to define energy, work and power Understand the role of ATP; the breakdown and re-synthesis of ATP; coupled reactions and exothermic and endothermic reactions

Energy Energy is the ability to perform work or put mass into motion When applied more directly, energy refers to the ability of the muscles to contract (kinetic energy) and apply force that may limit or increase performance in physical activity Energy is usually measured in joules (J), which is the unit to describe the force of 1 Newton (equivalent to 1 kilogram) acting through a distance of 1 metre. Energy is also measured in calories, where 1 calorie is equal to 4.18 joules

Work Work is done when a force is applied to a body to move it over a certain distance It is expressed as: Work = force (N) x distance moved (m) The units of measurement for work are joules (j)

Power Power is the rate at which work can be done i.e. work divided by time. Hence power is force multiplied by distance divided by the time taken Work force (N) x distance (m) Power =time = time (seconds) The units of measurement for power are watts (W) In simple terms, force multiplied by distance represents pure strength, but when divided by time it represents speed

Athlete weight (kg) 100m time (seconds) Power (W)Rank Rank the 100m sprinters from most powerful (1) to the least powerful (4)

Spend some energy Design an experiment that will allow you to measure how much energy you have used for motion What equipment will you need? What results do you need to find? What did you discover remembering your Basal Metabolic Rate?

ATP Adenosine triphosphate (complex element) One molecule of Adenosine (3 simple elements) Three phosphate molecules moves/revise-it/skeletal-muscles moves/revise-it/skeletal-muscles Held together with high energy bonds

Releasing energy ATPase – enzyme Breaks the bond between the last 2 phosphates Exothermic reaction (energy exiting – being given off) Leaves ADP Adenosine diphosphate

ATP re-synthesis Energy was released by splitting the molecules, so energy will be needed to re-synthesise Where does this energy come from 3 Energy systems 1. ATP/PC 2. Lactic acid 3. And Aerobic