energy p1 Flashcards
What is a system?
A system is an object or group of objects.
How does the energy storage change when a system changes?
The way energy is stored also changes.
What happens when a ball rolls and hits a wall?
The system is the moving ball, and some of the kinetic energy is transferred as sound.
What occurs when a vehicle slows down?
Kinetic energy transfers to thermal energy due to friction between wheels and brakes.
What is the formula for calculating kinetic energy?
Ek = 1/2 mv²
Kinetic Energy = 1/2 * mass * (velocity)^2
In the kinetic energy formula, what does ‘m’ represent?
‘m’ is the mass in kilograms, kg.
In the kinetic energy formula, what does ‘v’ represent?
‘v’ is the speed in metres per second, m/s.
What is elastic potential energy?
The type of energy stored in a spring when it is stretched.
What is the formula for elastic potential energy?
Ee = 1/2 ke²
elastic potential energy = 1/2 x spring constant x extension²
In the elastic potential energy formula, what does ‘k’ represent?
‘k’ is the spring constant in newtons per metre, N/m.
What does ‘e’ represent in the elastic potential energy formula?
‘e’ is extension in metres, m.
What is the formula for gravitational potential energy?
Ep = mgh
gravitational potential energy = mass x gravitational field strength x height
In the gravitational potential energy formula, what does ‘g’ represent?
‘g’ is the gravitational field strength (9.8 m/s²) in newtons per kilogram, N/kg.
What does ‘h’ represent in the gravitational potential energy formula?
‘h’ is the height in metres, m.
What is specific heat capacity?
The energy required to raise the temperature of 1kg of a substance by 1°C or 1K.
What is the formula for calculating thermal energy change?
E = mcΔT
In the thermal energy change formula, what does ‘c’ represent?
‘c’ is the specific heat capacity in joules per kilogram per degree Celsius, Jkg⁻¹°C⁻¹.
What is power?
Power is defined as the rate at which energy is transferred or the rate at which work is done.
What is the formula for power?
P = E/t = W/t
In the power formula, what does ‘P’ represent?
‘P’ is in watts, W.
What does an energy transfer of 1 joule per second equal to in power?
1 watt.
True or False: Energy can be created and destroyed.
False.
What is meant by energy being ‘wasted’?
In all system changes, energy is dissipated and stored in less useful ways.
How can energy waste be reduced?
By using lubrication and thermal insulation.
