WORK AND ENERGY MASTERAL

1. WORK AND ENERGY EMILY B. ALIDO MAED SCIENCE

2. WORK Work is done when a force is applied to an object and the object moves in the direction of the force. Work= Force X Distance ENERGY is the ability to do work. TYPES OF ENERGY: Kinetic energy (energy of motion) and potential energy (stored energy) ENERGY

3. WORK-ENERGY THEOREM☻The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy:W= ΔKE= 1/2m (v2f- v2i)☻This relates the concepts of work and energy by showing that doing work on an object transfers energy to or from it. Presentation title

4. KINETIC AND POTENTIAL ENERGY ☻Kinetic Energy (KE): The energy an object has because of its motion. KE= 1/2mv2 ☻Potential Energy (PE): The energy stored in an object due to its position or configuration. PEgravitational= mgh ☻Both types of energy can be converted into each other, such as when a ball is dropped (PE to KE).

5. CONSERVATION OF ENERGY Law of Conservation of Energy: Energy cannot be created or destroyed, only transformed from one form to another. In a closed system, the total mechanical energy (sum of KEand PE) remains constant:Etotal= KE+PE Example: A pendulum swings between maximum potential energy (at the highest point) and maximum kinetic energy (at the lowest point).

6. POWER☻The rate at which work is done or energy is transferred.P=w/t☻Power is measured in watts (W), where 1 watt equals 1 joule per second.Example: A person climbing stairs uses power to lift their body weight.

7. LABORATORY ACTIVITY:WORK AND ENERGY EXPERIMENT Materials: 1. Pulley system 2. Weights 3. Spring scale 4.Ruler or measuring tape

8. PROCEDURE: 1. Attach a weight to a string and pass it over a pulley. 2. Measure the force required to lift the weight using the spring scale. 3. Measure the distance the weight is lifted. 4. Calculate the work done: W= Fxd 5. Observe the potential energy gained by the weight at different heights: PE= mgh 6. Discuss energy transformations between kinetic and potential energy as the weight is lifted and lowered.

9. ☻In the experiment, the work done to lift the weight is equal to the increase in its potential energy. • ☻Energy is conserved during the process, demonstrating the work-energy theorem. • Discussion Questions: • ☻How does increasing the height affect the potential energy? • ☻What factors influence the amount of work done? • ☻How does this relate to real-world application like elevators or cranes? DISCUSSION AND CONCLUSION

10. Your ability to communicate effectively will leave a lasting impact on your audience Effectively communicating involves not only delivering a message but also resonating with the experiences, values, and emotions of those listening  Speaking impact LINEAR MOMENTUM ☻Linear momentum (p) is the product of an objects mass (m) and its velocity (v). p=mxv ☻It is a vector quantity, meaning it has both magnitude and direction. ☻Units: Kilogram-meter per second (kg.m/s). Presentation title

11. CONSERVATION OF LINEAR MOMENTUM Law of Conservation of Momentum: In a closed system with no external forces, the total momentum before a collision or interaction is equal to the total momentum afterward. Σp_initial = Σp_final This principle is crucial in analyzing collisions and explosions.

12. Impulse and Momentum Impulse (J) : The change in momentum caused by a force acting over a period of time. J = F x ∆t = ∆p Impulse is equal to the change in momentum. A larger impulse leads to a greater change in momentum. This helps explain how airbags reduce injuries by increasing the time over which they stop passengers.

13. TYPES OF COLLISIONS Elastic collisions : Both momentum and kinetic energy are conserved. example: Two billiard balls colliding. Inelastic Collisions: Momentum is conserved, but kinetic energy is not. example: A car crash where the vehicles stick together. The total momentum before and after collisions remains constant, but energy may be lost as heat, sound, etc.

14. CENTER OF MASS AND MOTION The center of mass is the point where the mass of a system or object is concentrated. In a collision, the center of mass continues to move in the same direction unless acted on by an external force. Example: The center of mass of two colliding objects continues to follow a predictable path, even if the individual objects motion changes drastically.

15. LABORATORY ACTIVITY- INVESTIGATING MOMENTUM AND COLLISIONS Objective: Investigate the conservation of momentum in elastic and inelastic collisions. Materials: •Two dynamic carts (with different masses) •Track •Motion sensors or rulers balance (to measure mass) •Velcro strips ( for inelastic collision )

16. PROCEDURE 1. Measure and record the mass of both carts. 2. Place the carts on the track and push them towards each other for different types of collision. 3. Use motion sensors or rulers to measure the velocity of each cart before and after the collision. 4. Calculate the momentum for each cart before and after the collision: p=m x v 5. Investigate both elastic (without velcro) and inelastic (with velcro) collision. 6. Compare the total momentum before and after each type of collision.

17. DISCUSSION AND CONCLUSION Results: • In both elastic and inelastic collisions, the total momentum is conserved. • In elastic collisions, kinetic energy is also conserved, while in inelastic collisions, kinetic energy is not. Discussion and Questions: 1. How does the mass of the carts affect the momentum before and after the collisions? 2. What happens to the velocity after inelastic collisions? 3. How does impulse relate to the force applied during the collision?

18. CONCLUSION The experiment confirms the conservation of momentum principle in different types of collisions and highlights the importance of external forces on momentum changes.

19. Thank you