Topic 2 - Motion And Forces

Question 1

balanced force

Answer 1

when the result of all the forces on an object is zero

Question 2

unbalanced force

Answer 2

non-zero resultant force on an object

Question 3

Newton’s first law

Answer 3

an object at rest stays at rest and an object in motion stays in motion with the same speed, and in the same direction unless acted upon by an unbalanced force

Question 4

when drawing a force how do you show the size of that force

Answer 4

length of the arrow

Question 5

resultant force

Answer 5

the overall force acting on an object

Question 6

how do you work out the resultant force if the forces are acting in the same direction

Answer 6

add them

Question 7

how do you work out the resultant force if the forces are acting in opposite direction

Answer 7

subtract one from the other

Question 8

centripetal force

Answer 8

the name given to these types of unbalanced force that causes circular motion
—> centripetal forces always act to pull an object into the middle of the circle

Question 9

mass (kg)

Answer 9

the amount of a matter there is in an object

Question 10

weight (N)

Answer 10

the force pulling on an object downwards

Question 11

what’s the earths gravitational field strength

Answer 11

9.8N/kg (10N/kg)

Question 12

weight equation

Answer 12

weight (N) = mass (kg) x gravitational field strength (N/kg)

Question 13

what forces act upon a falling object

Answer 13

weight/gravitational potentional energy ⬇️
air resistance/drag⬆️

Question 14

Newton’s second law of motion

Answer 14

non-zero resultant forces acts on an object, then it will cause the inject to accelerate
- the acceleration in the direction of a resultant force depends on: the size of the force, the mass of the object

Question 15

circular motion

Answer 15

is a movement of an object along the circumference of a circle or rotation along a circular arc

Question 16

why is an object that moved in a circular motion always accelerating

Answer 16

because although the speed remains constant, it’s always changing its direction as it moves round an object so therefore is always accelerating
(the centripetal force is always perpendicular to the direction the object is moving in circular motion)

Question 17

equation to work out the force needed to accelerate a particular object

Answer 17

force (N) = mass (kg) x acceleration (m/s2)

Question 18

Newton’s third law

Answer 18

for every action (force) has is an equal and opposite reaction

Question 19

equilibrium in physics

Answer 19

if the size and direction of the forces acting on an object are exactly balanced, then there is no net force acting on the object and the object is said to be in equilibrium

Question 20

what type of object does balanced forces act upon

Answer 20

the same

Question 21

what type of object does an action-reaction force act upon

Answer 21

different objects

Question 22

force

Answer 22

a push or pull that acts on an object due to the interaction with another object
-> forces are vector quantities because they have both magnitude and direction

Question 23

what two things affect someone’s weight

Answer 23

mass and how strong the gravity is

Question 24

terminal velocity

Answer 24

the maximum speed at which an object will fall

Question 25

what happens to the forces in a collision

Answer 25

when two objects collide, they both exert a force on the opposite object; these forces are the same size but necessarily do not have the same effects on the two objects because they have different masses

Question 26

momentum

Answer 26

a measure of how much motion an object has

Question 27

momentum word equation

Answer 27

momentum (kg m/s) = mass (kg) x velocity (m/s)

Question 28

momentum symbol equation

Answer 28

p = m x v

Question 29

equation needed to work out the force used for momentum

Answer 29

force = change in momentum or mv - ma time t

Question 30

if you have more mass what does that mean for your momentum

Answer 30

objects with more mass have more momentum

Question 31

conservation of momentum

Answer 31

when moving objects collide, the total momentum of both objects is the same before the collision, as is after the collision, as long as there is no external forces acting

Question 32

thinking distance

Answer 32

the time for the driver to react to the problem while the vehicle travel some distance

Question 33

breaking distance

Answer 33

the car will then travel a little bit more while the brakes are working to bring it to a halt

Question 34

stopping distance

Answer 34

the overall sum (+) of the thinking and braking distances

Question 35

reaction time

Answer 35

time person detecting a stimulus (e.g. flashing lights or a sound) and their response (e.g. pressing a button or applying brakes)

Question 36

what can affect your reaction time

Answer 36

if the person is tired, ill answer has been taking drugs or drinking alcohol

Question 37

what can distract you from a quick reaction time

Answer 37

your phone

Question 38

what can increase the braking distance

Answer 38

if the roads are or has loose gravel, tyres are worn, brakes are worn

Question 39

how does a car break

Answer 39

the brakes use friction to slow the car down

Question 40

what does it mean for breaking distance increases

Answer 40

it means there’s less friction being created so the braking distance is increased

Question 41

work done

Answer 41

work is done is when energy is transferred from one store to another over a distance -> the amount of energy transferred depends on the size of the force and how far the object moves while the force is pushing it

Question 42

work done word equation

Answer 42

work done (J) = force x distance moved in the direction of the force (m)

Question 43

kinetic energy

Answer 43

the energy stored in a moving object -> the amount of kinetic energy depends on the mass object and its velocity

Question 44

kinetic energy word equation

Answer 44

kinetic energy (J) = 1/2 x mass (kg) x speed squared (m/s squared)

Question 45

what happens to the kinetic energy when a vehicle stops

Answer 45

the kinetic energy is transferred to other energy stores by the braking force

Question 46

crumple zone

Answer 46

the zone at the front of the car which absorbs impact energy during a collision so that the deceleration and force is less (less of an impact)

Question 47

inertial mass

Answer 47

a measure of an object's resistance to acceleration when a force is applied; it is determined by applying a force to an object and measuring the acceleration that results from that force.

Question 48

inertial mass equation

Answer 48

force / acceleration

Question 49

what’s the difference between inertial mass and gravitational mass

Answer 49

Inertial mass is measured by measuring an object's resistance to changes in velocity; while gravitational mass describes the force on an object in a gravitational field.

Question 50

what is the practical in investigating acceleration

Answer 50

- using trolleys to investigate the effects of mass and force having acceleration - the force will be provided by mass hang on a string

Question 51

what are action-reaction forces

Answer 51

- They a pair of forces acting on the two interactive objects - two forces are always the same size and an opposite directions but always the same type of force (e.g. pulling forces, gravitational forces etc.)

Question 52

equilibrium in physics

Answer 52

The state of balance between opposing forces of actual static (as in a body acted on by forces whose resultant is zero)

Question 53

what’s the difference between action reaction forces and balanced forces?

Answer 53

- Action reaction forces act on different objects - Balanced forces all act on the same object

Question 54

unit for momentum

Answer 54

kg m/s

Question 55

air resistance

Answer 55

a frictional force that opposes the motion of objects moving quickly through the air; the force due to air resistance increases as the speed of a falling object increases.

Question 56

inertia

Answer 56

measure of how difficult it is to change the object's motion

Question 57

Write the process to investigate acceleration (CORE PRACTICAL)

Answer 57

- Put ramp on a slight slope so trolley starts to move a constant velocity on its own - keep the mass constant having all mass on the trolley and then moving one mass at a time onto the hanger from on the trolley attached to a string to the trolley - Use light gates to measure the velocity of the car at the start the end of its journey - Use the equation: a = V squared - U squared / 2 x distance - Repeat and calculate the average