Topic 9 Flashcards
non-contact force
magnetic force
electrical
weight
gravitational force
contact force
air resistance
friction
tension
upthrust
feild
a region where each point is affected by a force
magnetic fields
dipolar
north to south
closed loops around the magnet
electrical fields
radial shape
+ to -
monopolar
source is any charged object
gravitational fields
radial field
diraction- inwards
source- any object with mass
monopolar fireld
centre of mass
is the point where mass is evenly distributed around
gears
can be used to transfer rotational forces
they can also be used to magnify the speed of roatation or the force at the edge of teh wheel
gear a has more teeth than gear b
gear a has more teeth than gear b so for one complete revolution for gear a gear b will turn several times
the number of turns/ speed of roatation
depend on the ratio of number of teeth or the circumerence
On another day, Joe is riding the same bike on the same piece of road.
This time he does not have the heavy bag on his back.
He finds that it is easier to accelerate.
Explain why Joe finds it easier to accelerate
smaller mass
less force needed to accelerate
A rope can withstand a tension of 12 000 N before it breaks.
The weight of the car is 14 000N.
Discuss whether this rope could be strong enough to tow the car with the
truck.
The tow rope does not have to
support the weight of the car (1)
Tension is caused by accelerating
force (plus frictional forces) (1)
Tension is 5700 N (in this situation
)(1)
Forces could be kept below
12,000N (1)
If acceleration is kept small (1)
f = m x a (1)
Use ideas about pressure, force and area in your answer
same mass
but cylinder A has the smallest area (that is in contact with
the ground) (1)
* the smaller the area, the greater the pressure (or reference
to P = F ) (1)
* hence cylinder A exerts a greater pressure on the ground
