2a) Motion, Energy and Electricity Flashcards
What does the gradient represent in a distance-time graph and a velocity-time graph?
In a distance-time graph, gradient means speed
In a velocity-time graph, gradient means acceleration
Define the difference between speed and velocity
Speed is how fast you’re travelling
Velocity is speed in a direction or with a vector
What is gravity?
The force of attraction between all masses
How do you work out weight using mass and gravitational field strength?
W=mxg
What is the resultant force?
Overall force of an object
If there is a resultant force acting on an object, what will happen to the object?
Object will change it’s state of rest or motion or change its velocity (acceleration)
What happens is the resultant force on a stationary object is zero?
Object will remain stationary
If there is no resultant force on a moving object, what will happen?
Object will keep moving in the same direction at the same velocity
No change in velocity
When two objects interact, the forces they exert on each other are…..?
Equal and opposite
If an object has no force propelling it along, why would it slow down and stop?
Friction acts in the opposite direction to movement
How can you reduce drag or air resistance by changing the shape of a vehicle?
Streamlined
What happens to drag as speed increases?
Drag increases
What does the terminal velocity of falling objects depend on?
Their shape and area
What is stopping distance?
Distance covered in the time between the driver spotting a hazard and the vehicle coming to a complete stop
Sum of thinking distance and breaking distance
What things affect thinking distance?
How fast you’re going - faster speed = further distance
Brain state - affected by tiredness, drugs, alcohol, careless attitude
Bad visibility and distractions
What is thinking distance?
The distance the vehicle travels during the driver’s reaction time
What is braking distance?
The distance a car travels under the braking force
What is braking force affected by?
How fast you’re travelling - faster speed = further distance
Quality of brakes
Thickness of tyres - thicker tyres = better braking distance
Grip - affecting road surface, weather, tyres
What happens regarding forces when a force moves an object through a distance?
Energy is transferred
Work is done
How do you calculate work done?
Force x distance
What is gravitational potential energy?
Energy that an object has because of its vertical position in a gravitational field
What two things does kinetic energy depend on?
Mass - more it weighs, faster speed, bigger kinetic energy
Speed - faster, bigger kinetic energy
What does the conservation of energy state?
Energy can never be created it destroyed only converted into different forms
When something falls, what is it’s potential energy converted into?
Kinetic energy
