(1) resultant forces

Question 1

what can forces change

Answer 1

• the shape of an object
  -its state of rest
  -its motion

Question 2

give 3 examples of noncontact forces

Answer 2

-gravity
-electrostatic energy
-magnetism

Question 3

give 3 examples of contact forces

Answer 3

-friction
-air resistance
-tension

Question 4

whats the unit of force

Answer 4

Newtons

Question 5

what happens when 2 objects interact

Answer 5

they excert an equal and opposite force on eachother

Question 6

whats friction

Answer 6

a force that opposes the motion of any 2 surfaces in contact with eachother when they try to slide past eachother

Question 7

whats a resultant force

Answer 7

a single force that has the same effect as all the forces acting on an obhect

Question 8

what does newtons1st law of motion state about zero resultant force

Answer 8

if the resultant force on an object is 0, the object
-remains at stationary if it was at rest
or
-continues to move at the same speed and direction as it was

Question 9

if a resultant force is 0 and only 2 forces are acting on the object then..

Answer 9

those 2 forces must be equal and act in opposite direction to eachother

Question 10

what can we conclude when the resultant force is not 0

Answer 10

the forces acting on the object arent balanced

Question 11

hoe do vectors show the force of an object in diagrams

Answer 11

each force is reprsented by a vector which is shown as an arrow
-the length of the arrow is proportional to the size(magnitude) and point to the direction

Question 12

if an object is acted on by 2 unequal forces then the resultant force is..

Answer 12

-equal to the difference between the 2 forces
-in the direction of the larger force

Question 13

what does the parallelogram of forces show us

Answer 13

the resultant forces of 2 forces that dont act on the same line

Question 14

what are scalars

Answer 14

quantities that have ONLY a magnitude(size)

Question 14

whatre vector quantities and how are they represented

Answer 14

vectors have both direction and magnitude(size)
theyre represented by arrows. the length of an arrow shows the magntiude and the direction its pointing at shows us direction

Question 14

define weight

Answer 14

the force of gravity on an object due the gravitational attraction between the object and the earth

Question 15

whats the unit for weight and mass

Answer 15

weight- Newtons
mass- Kg

Question 16

whats the formula that relates weight,mass and gravitaty

Answer 16

w=mg
where w is weight in newtons
m is mass in kg
and g is gravitational field strength in N/Kg

Question 17

when can we call an object elastic

Answer 17

if it returns to its original shape after you remove the force deforming it

Question 18

whats an extention and how can you calculate it

Answer 18

an increase in length of a stretched material from its original length, its calculated each time a weight is added
extention=stretched length-original length

Question 19

whats the relationship between spring extentions and the force applied to it

Answer 19

theyre directly proportional, as long as limit of proportionallity(stretched beyond its limit) isnt exceeded

Question 20

whats the equation for hookes law

Answer 20

force=spring constant X extension

Question 21

what happens when an elastic object is stretched

Answer 21

elastic potential energy is stored in the object because work is done on the object by the stretching force