P3

Question 1

Proportional

Answer 1

If 2 variables are proportional then if one is doubled so is the other. If proportional variables are plotted on a graph then they will lie in a straight line with a positive/negative gradient which passes through the origin

Question 2

Line of best fit

Answer 2

It is drawn through real experimental data plotted on a graph and allows for a few anomalies due to inaccuracies in collecting the data. The line is drawn with a rule on the graph and it best represents the trend of points.

Question 3

Gradient

Answer 3

The slope of the graph. It is usually measured as the change in y (rise)/the change in x (run).

Question 4

Spring constant

Answer 4

a measure of the stiffness of the spring. It is measure in N/m or N/cm

Question 5

Spring constant equation

Answer 5

k=F/x. Spring constant= force/extension

Question 6

Force

Answer 6

a push, pull or twist applied to an object. It is measured in Newtons.

Question 7

Weight

Answer 7

the force of graviy acting on an object measured in Newtons, defined as W=mg where m is the mass of an object in kg and g is acceleration due to gravity in m/s/s or N’kg. On Earth, g=10N/kg

Question 8

Normal contact force

Answer 8

the upward push of the ground on an object measured in Newtons. It usually acts at 90 degrees to the surface and often is equal to the weight of the object but opposite in direction.

Question 9

Balanced forces

Answer 9

If all forces acting on an object cancel each other out so that the resultant/ total force is 0.

Question 10

Unbalanced forces

Answer 10

If the forces acting on an object have a resultant force when added up. An unbalanced force may cause an object to accelerate, change direction or both.

Question 11

Equilibrium

Answer 11

If all forces acting on an object are balanced. This means that the object will continue to move at a constant velocity. A stationary object (velocity=om/s) is also at an equilibrium

Question 12

Friction

Answer 12

a resistance force which opposes the motion of an object, caused when 2 surfaces rub against each other

Question 13

Air resistance

Answer 13

a resistive force which opposes the motion of an object, caused when an object moves through air. The air molecules collide with the object and oppose the motion

Question 14

Free body diagram

Answer 14

A diagram which illustrates all the forces acting on an object. The object is usually represented by a point or a small box. The forces are drawn on the object as arrows and are shown acting in the correct direction. The larger the arrow, the bigger the force

Question 15

Newton’s first law

Answer 15

If the forces acting on an object are balanced, the object remains in equilibirum i.e it will continue to move at a constant velocity (which may be at 0)

Question 16

Newton’s second law

Answer 16

If an unbalanced force, F, acts on an object then the acceleration of the object, a, may be calculated using F=ma where m is the mass in kg

Question 17

Extension of the spring

Answer 17

shows how much its length has increased from its original length. Extension= Stretched length-original (unloaded) length

Question 18

Elastic

Answer 18

An elastic material changes shape when an external force is applied but returns to its original shape when the force is removed

Question 19

Extension

Answer 19

The extension of a spring is the difference between the stretched length and the natural length

Question 20

Hooke’s law

Answer 20

Force applied is proportional to the extension, or F=kx