paper one Flashcards
(53 cards)
what does the gradient of the line on a distance-time graph show?
speed
what does it mean when the line is stationary on a distance-time graph show?
shows the object is stationary
what is the relationship between speed, distance, and time?
speed = distance/time
what is the relationship between acceleration, velocity, and time?
acceleration = change in velocity/time
what does the gradient of the line of a velocity time graph show?
the acceleration
what does the area under the line on a velocity time graph show?
distance travelled
what does it mean if the line is flat on a velocity time graph?
the object is moving at a constant speed
what is the relationship between speed, acceleration, and distance?
v2 = u2 + (2as)
what are the different forces?
- up thrust
- lift
- thrust
- weight
- friction
- drag
- magnetic
- electrostatic
- normal reaction
is force a vector or a scalar quantity?
vector
what are scaler quantities?
quantities with only magnitude
what are vector quantities?
quantities with magnitude and direction
what is friction?
a force that opposes motion
what is the relationship between force, mass, and acceleration?
F=ma
what is stopping distance the sum of?
thinking distance and braking distance
what factors affect thinking distance?
- tiredness
- alcohol
- speed of car
- age
- drugs
what factors affect braking distance?
- road conditions
- tyre conditions
- brake conditions
- speed of car
- mass of car
what part of a force-extension graph is associated with Hooke’s law?
the initial linear region
what is elastic behaviour?
the ability of a material to recover its original shape after the forces causing deformation have been removed
what is insulation and how does it protect the user?
insulation is when the wires are covered in a insulating material and protects the user by preventing them touching the current-carrying wire, so it lowers the risk of electrocution
what is double insulation and how does it protect the user?
they have insulated wires and a non-metallic casing which acts as a second layer of protection. double insulated devices do not need to be earthed as the insulating casing cannot be electrified so there is less/no risk of electrocution for the user
what is earthing and how does it protect the user?
if an appliance with a metal casing has the live wire come into contact with the casing, it will be electrified and anyone who touches it could be electrocuted. an earth wire is an additional layer of protection in case this happens, as if the metal case gets electrified, the earth wire will provide a low resistance path to the earth, and it will get a surge of current, which means there will be a surge in current in the live wire too. the high current causes the fuse to melt and break and so the circuit is broken, so there is no more electricity going to the appliance, so there is no risk of electrocution
what is a fuse and how does it protect the user?
it is a safety device that is designed to break the circuit if the current becomes to high. it contains a thin wire which will melt if the current goes above a certain value, which isolates the appliance and prevents damage to the device. if the fuse melts, it has to be replaced
what is a circuit breaker and how does it protect the device?
a circuit breaker is designed to break the circuit if the current is too high. it has an push switch which is spring loaded. if the current is too high, the electromagnet will push the switch down by pulling the bolt of the switch (which holds the push switch in place). this will break the circuit, and so it isolates the appliance and prevents the risk of damage to the appliance. they are more reliable and sensitive than fuses, and do not to be replaced, only reset
