Forces and Motion Flashcards
(18 cards)
What does hookes law state
Extention is directly proportional to force (on a diagram it would be a straight line)
Describe initial velocity after freefall
- only weight acts downwards as a resultant force
- so first acceleration
- then drag increases with speed
- then terminal velocity is reached
- where forces are now balanced
what would happen if a parachute was opened during terminal velocity
large increase in air resistance, and sloing down until weight and air resistance are equal again
what is a force
a push or pull that arises from the interaction between forces
what is reaction force
when an object rests on a surface, the surface exerts a push force on the object which acts at a right angle to surface
what is thrust
a force produced by an engine that speeds up its motion
what is upthrust
fluid exerting an upward acting push force on an object
example of a force changing direction of something
gravitational attraction of the sun can change the direction of a comet
what are scalar quantities
quantities that have a magnitude but no direction - distance, speed, mass
define friction
a force which opposes the motion of an object
factors affecting breaking distance
- vehicle speed
- vehicle mass
- road conditions
- reaction time
define elastic behaviour
ability of a material to recover its original shape after the forces have been removed
force equals change in momentumβ¦
over time
What does the gradient tell you on a velocity time graph
Acceleration
Newtonβs first law
Balanced forces mean no change in velocity
newtons third law
when two objects interact, the forces they exert on each other are equal and opposite
example of newtons third law
when a skateboarder jumps off a skateboard, they apply a psuh force onto the skateboard
which causes the skateboard to move right, at the same time the skateboard pushes back on the skateboarder
velocity time graph of a skydiver
up, then straight, then down, then straight
