Forces and motion / Mechanics (OCR Physics A)

4.8 (12 reviews)
newton
Click the card to flip 👆
1 / 35
Terms in this set (35)
newton
The force which gives a mass of 1kg an acceleration of 1ms^-2.
joule
The work done by a force of 1 N moving an object 1 m in the direction of the force.
watt
The power transferred by one joule per second.
displacement
the distance moved by an object in a particular direction
instantaneous speed
the speed at the precise instant that it is measured (e.g. a car's speedometer)
average speed
the speed calculated during a period of time
speed
rate of change of distance
velocity
rate of change of displacement
acceleration
rate of change of velocity
density
mass / volume
torque of a coupleone of the forces x perpendicular distance between the forces.moment of a forceforce x perpendicular distance from pivot.work done by a forceforce x distance moved in the direction of the forcepowerthe rate of work doneforce constant of a springforce per unit extensionscalara quantity with magnitude onlyvectora quantity with both magnitude and directionterminal velocitythe velocity of a falling object when weight = dragcentre of gravitya point where the entire weight of an object appears to actthinking distancethe distance travelled by the car in the time taken by the driver to reactbraking distancethe distance travelled by the car after the brakes are applied until the car stopsstopping distancethinking distance + braking distanceprinciple of conservation of energyEnergy cannot be created or destroyed; it can only be transferred into other formsprinciple of momentsFor an object in equilibrium, the sum of the clockwise moments about a point = the sum of the anticlockwise moments about the same pointHooke's lawextension of a spring is proportional to the force applied (as long as the elastic limit is not exceeded)stress= force / areastrain= extension / original lengthYoung modulus= stress / strain, as long as the elastic limit is not exceededultimate tensile strengththe breaking stress of a materialelastic deformationmaterial returns to original shape when the force is removedplastic deformationmaterial does not return to original shape when the force is removedArchimedes' Principlethe upthrust is equal to the weight of the fluid displacedNewton's First LawAn object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.Newton's Second LawThe net force on an object is proportional to the rate of change of momentumNewton's Third LawFor every action force there is an equal and opposite reaction force