1.1-1.24 Flashcards
Velocity
The speed of an object in a given direction
Distance/ time graph
Distance y axis
Time x axis
Speed/ time graph
Speed y axis
Time x axis
Distance travelled of a speed/time graph
Area under the graph
final speed equation (SUVAT)
v2 = u2 + (2 × a × s)
Effects of forces
Forces can act on a body to change the velocity, so the speed, direction or both.
Or forces can change the shape of a body stretching it, squishing it or twisting it.
different types of forces:
Weight, tension, friction, air resistance, normal, thrust, lift and upthrust
Weight
Pulls an object towards the center of a large mass
Tension
A force in a rope or cable being pulled
Friction
A counter force caused when two object rub together
Air resistance
A counter force produced when an object travels through the air
Normal
Upward force from a surface to counter weight
Thrust
A pushing force (e.g. by an engine / rocket)
Lift
Upwards force on a plane or helicopter
Upthrust
Upwards force in water
Vector
A vector is both magnitude (size) and direction
Scalar
When something is not a vector (doesn’t have size or direction)
Force is a vector quantity
Force has a magnitude measured in (N) but it also has a direction, a push or a pull, up, down, left or right. So force is a vector.
Friction always act in the …. direction to motion
opposite
force equation
force = mass x acceleration
Weight equation
weight = mass x gravitational field strength (10)
Sum of stopping distance
Thinking distance + breaking distance
Factors that affect thinking distance
Tiredness, alcohol consumption, medicines, drugs (avoid it) and phone
Factors that affect breaking distance
Wet roads, icy roads, driving too fast, breaks worn out, tyres worn out.
forces acting on falling objects
1) At the start of his jump the air resistance is 0 so he accelerated downwards
2) As his speed increases air resistance increases
3) Eventually air resistance will be enough to equal his weight. The forces become balanced so his speed is constant (Terminal velocity)
Hooke’s law
extension is directly proportional to force applied. This is shown by the straight line on the force-extension graph. Hooke’s law is obeyed as long as the line is straight.
Elastic behaviour
the ability of a material to recover its original shape after the forces causing deformation have been removed
