Slides in this set
· Moment = turning effect of a force.
· Larger force = larger moment.
· Larger perpendicular distance from line of action to pivot = larger moment.
· Maximum moment = exert force perpendicular/at right angles to pivot.
MOMENT (Nm) = FORCE (N) X PERPENDICULAR DISTANCE (m)
· Centre of mass = point at which whole mass is concentrated.
· An object will swing until it's centre of mass is directly below the pivot.
FINDING CENTRE OF MASS:
· Suspend shape and plumb line from same point, wait until they stop moving.
· Draw line along plumb line.
· Repeat from a different point.
· Centre of mass = where two lines cross.
· Where lines of symmetry cross.…read more
· Stable object = total anticlockwise and clockwise moments are equal.
· Anticlockwise and clockwise moments not equal = resultant moment.
· Most stable = wide base, low centre of mass.
· Unstable/ tips over if centre of mass moves outside it's base as weight
doesn't act in line with pivot causing a resultant moment.…read more
· Velocity = speed and direction of object.
· Travelling in circle = velocity constantly changing, accelerating.
· Force acting on it = towards centre of circle = centripetal force.
· Car going around a bend = centripetal force is friction.
· Spinning fairground ride = centripetal force is tension.
· Earth orbiting the sun = centripetal force is gravity.
· Faster object is moving = bigger centripetal force.
· Heavier object = bigger centripetal force.
· Smaller circle = bigger centripetal force.…read more
Saturn has a longer orbit than
Mercury as it is further away from
· Gravity = forces of attraction between the sun.
· Larger mass = greater force of gravity.
· Gravity = acts as centripetal force in orbits.
· Planets always orbit stars.
· Orbits = elliptical (elongated circles).
· Further distance = longer orbit takes.
· Gravity decreases as you get further away.…read more
· High orbits over equator.
· 24 hours to complete an orbit.
· Stay above same point on Earth Earth rotates with them.
· Uses = communication e.g. phone signals as in same place.
LOW POLAR ORBIT
· Sweeps over both poles Earth rotates beneath it.
· Takes 2-3 hours.
· Whole surface can be monitored in a day.
· Uses = weather, spying as low orbits, monitors larger areas.…read more