Modelling assumptions

Question 1

What is gravity?

Answer 1

The force of attraction between all objects.

Question 2

Give assumptions of gravity.

Answer 2

.Assume all objects with mass are attracted to earth
. Earths gravity is uniform and acts vertically downwards.

Question 3

What is air resistance?

Answer 3

resistance experienced as an object moves through the air.

Question 4

Give an assumption of air resistance.

Answer 4

Usually modeled as being negligible.

Question 5

What is peg?

Answer 5

A support from which a body can be suspended or rested.

Question 6

Give an assumption of peg.

Answer 6

. dimensionless and fixed
. can be rough or smooth

Question 7

What is bead?

Answer 7

a particle with a hole in it for string or wire.

Question 8

Give an assumption of bead.

Answer 8

. Moves freely along a wire or string
. tension is the same on either side of the bead.

Question 9

What is smooth and light pully?

Answer 9

They are a pully that are smooth and light.

Question 10

Give an assumption of a smooth and light pully.

Answer 10

.pully has no mass
. tension is the same on either side of the pully.

Question 11

What is a wire?

Answer 11

rigid thin length of metal.

Question 12

Give an assumption of a wire.

Answer 12

. treated as one-dimensional.

Question 13

What is a rough surface?

Answer 13

when a surface is not smooth.

Question 14

Give an assumption of a rough surface.

Answer 14

.objects in contact with the surface experience friction if they are moving.

Question 15

Give an assumption of a smooth surface.

Answer 15

assume that there is no friction between the surface and object.

Question 16

What is an inextensible string?

Answer 16

a string that doesnt stretch.

Question 17

Give an assumption of an inextensible string.

Answer 17

. acceleration is the same in objects connected by an inextensible string.

Question 18

What is a light object?

Answer 18

mass of the object is small compared to other masses.

Question 19

Give an assumption of a light object.

Answer 19

. treat object as having zero mass

Question 20

What is a uniform body?

Answer 20

mass is distributed evenly

Question 21

Give an assumption of a uniform body.

Answer 21

mass of the object is concentrated at a single point- the center of mass.

Question 22

What is a Lamina?

Answer 22

object with area but negligible thickness like a sheet of paper.

Question 23

Give an assumption of a lamina.

Answer 23

mass is distributed across a flat surface

Question 24

What is a rod?

Answer 24

all dimensions but one are negligible like a pole or beam.

Question 25

Give an assumption of a rod.

Answer 25

. mass is concentrated along a line
. no thickness

Question 26

What is a particle?

Answer 26

dimensions of the object is negligible.

Question 27

Give an assumption of a particle.

Answer 27

mass of the object is concentrated at a single point.