Work and power Flashcards
What is the formula for calculating work done?
Work done = force x distance moved (in one direction)
Work is measured in joules, force in newtons, and distance in metres.
What is required for work to be done?
Movement
Work requires force to be applied to move an object.
What happens when you push something along a rough surface?
You are doing work against friction
This indicates that work is affected by the surface’s resistance.
What is the relationship between work done and energy transferred?
Work done = energy transferred
This highlights the concept that work results in energy movement.
When pushing something along a ramp, what distance should be considered?
The height, not the diagonal distance
This is important for calculations involving work and energy.
What is the formula for gravitational potential energy (GPE)?
Gravitational potential energy = mass x gravitational field strength x height
GPE can also be calculated as weight x height.
What is the unit of measurement for gravitational potential energy?
Joules
Mass is measured in kg, gravitational field strength in N/kg, and height in metres.
What is the formula for calculating change in gravitational potential energy?
Change in gravitational potential energy = mass x gravity x change in height
This formula helps determine energy changes when lifting objects.
What does lifting an object up require?
Work
This work transfers energy to the gravitational energy store.
What is the formula for kinetic energy?
Kinetic energy = ½ x mass x velocity²
Kinetic energy is measured in joules, mass in kg, and velocity in m/s.
How can speed be calculated from kinetic energy?
Speed = square root of (kinetic energy / ½ x mass)
This formula allows for the determination of speed based on energy and mass.
What happens to energy when an object moves?
Energy is transferred to or from the kinetic energy store
Energy is added when speeding up and removed when slowing down.
What occurs when something falls?
Energy is transferred from the gravitational potential store to the kinetic energy store
This process involves energy conversion due to gravitational force.
What effect does air resistance have on falling objects?
Some energy is transferred to other energy stores, e.g., thermal energy
This indicates that not all energy converts to kinetic energy due to external factors.
Where does the energy in humans come from?
Chemical energy from muscles and food
This highlights the biological aspect of energy sources for activity.
