Physics Flashcards
What is the definition of temperature
how fast the speed of molecules move that make up an object
What does the specific heat capacity of a material tell us
how much heat energy needs to be added or removed to change 1 kg of the material by 1 C
What is the equation for heat energy transferred
mass x specific heat capacity x change in temperature
What is the triangle for heat energy transferred
Heat energy transferred on the top and everyting else on the bottom
The specific heat capacity of water is J/kg/°C. How much energy is needed to heat 3 kg of water from 20°C to 40°C?
4200 x 3 x (40-20)=252000
What is internal energy
the total energy stored by the particles making up a substance or system
What are the 2 parts to internal energy
kinetic energy stores and potential energy stores
What consists in potential energy stores
gravitational,elastic energy
What is the kinetic energy store
the movement energy of particles
What energy store is used when you heat up a substance
the kinetic energy store increases
What is temp
a measure of the average internal energy in a substance
How much energy does it take to increase the temp of 1kg of mercury by 1 C
139
If you were to measure the temp change what are precautions to take and why
add a lid to the liquid and insulate it well,this is so energy isn’t lost to the surroundings
What is acceleration
the rate of change in velocity
What is the first equation for acceleration
change in velocity/time
What is the second equation for velocity
Final velocity-intial velocity/time
Calculate the velocity if a car accelerates from 15 m/s to 35 m/s in 5 seconds
Final velocity-initial velocity/time
35-15/5=4
What is the third equation for velocity
2as=v sq -u sq
a=acceleration
s=distance
v=velocity
u=initial velocity
A ball is dropped from an unknown height from above the ground the ball is moving at 7 m/s.Calculate the height from which the ball is dropped
final velocity=7
initial velocity=0
anything dropped accelerates at 9.8 m/s because of gravity
acceleration=9.8 m/s
distance=7 sq- 0 sq/2(9.8)
=49/19.6=2.5
s=2.5m
What is a typical walking speed
1.5 m/s
What quantity is the rate of change of velocity?
acceleration
How is speed found from a distance time graph
it is equal to the gradient
How is velocity found from a velocity-time graph?
Velocity is read from the vertical (y) axis of a velocity-time graph.
How is acceleration found from a velocity-time graph?
Acceleration is found from the gradient of a velocity-time graph.
What is the acceleration of a horse that accelerates from rest to 4 m/s in 8 seconds?
0.5 m/s
What is the unit of acceleration?
m/s sq
What is a typical acceleration for a family car?
3 m/s sq
What is the average speed of a runner that travels 200 m in 40 seconds?
5 m/s
How is distance travelled found from a velocity-time graph?
Distance travelled is found from the area beneath a velocity-time graph.
how do you calculate resistance
voltage/current
What happens when you combine resistors in series
The total resistance always increases.
What is the rule of combining resistors in a series
the total voltage (or potential difference) across all the resistors is equal to the sum of the voltages across each resistor.
What happens when you combine resistors in parrallel
The total resistance decreases and is always less than the smallest individual resistor.