Forces - Forces And Their Effects

Question 1

when you apply more than one force to an object, what may the object do

Answer 1

change shape

e.g. stretch, compress or bend

Question 2

what does it mean when an object has been inelastically deformed

Answer 2

cannot return to original shape

Question 3

what is the equation that links force to extension

Answer 3

force = spring constant x extension

Question 4

what is spring constant measured in

Answer 4

N/m

Question 5

what does spring constant measure

Answer 5

stiffness, the higher the spring constant, the stiffer

Question 6

what is the limit of proportionality

Answer 6

the limit of how much force you can apply to an object for the extension to be proportional

Question 7

on a force extension graph, what goes on what axis

Answer 7

y = force
x = extension

Question 8

how do you work out the energy stored in the elastic potential energy store using a force extension graph

Answer 8

its the area under the graph

Question 9

what is a moment

Answer 9

turning effect of a force

Question 10

what is the equation for a moment of a force (Nm)

Answer 10

force x perpendicular distance from the line of action of the force

a line at a right angle that connects the line of the force to the pivot

Question 11

what happens if the clockwise moment and anticlockwise moment about a pivot are equal

Answer 11

it is balanced and wont move

Question 12

how do levers make it easier to do work

Answer 12

increase distance from the pivot at which force is applied so less force is needed to get the same moment

Question 13

what do gears do

Answer 13

transmit the rotational effect of a force from one place to another

Question 14

what would happen to the moment if you transmit a force from a smaller gear to a larger one

Answer 14

cause a bigger moment

Question 15

what is a fluid

Answer 15

substances which their particles can move around so they can flow

these are liquids and gasses

Question 16

how would you calculate pressure at the surface of a fluid

Answer 16

force/ area

Question 17

what 2 factors can effect the pressure of a liquid

Answer 17

the density. the more dense, the more particles collide

the depth. as depth increases, the number of particles above that point increase and the weight of these particles increases pressure

Question 18

how would you calculate pressure at a certain depth in a column of liquid

Answer 18

depth x density x gravitatonal field strength

Question 19

what are the 2 reasons atmospheric pressure decreases with higher altitudes

Answer 19

density. as altitude increases, the atmosphere becomes less dense so there are fewer air molecules that can collide with a surface

high there are fewer air molecules above a surface. so there is less weight of air above

Question 20

what is upthrust and how does it work

Answer 20

a resultant force upwards in water

pressure increases with depth so their is a greater pressure at the bottom of the object

the upthrust is equal t the weight of the fluid that has been displaced

Question 21

what about the relationship between up thrust and the object determines weather it floats or sinks

Answer 21

if the objects weight is more than the up thrust then it sinks. if its equal than the object floats.