Force

Question 1

Speed

Answer 1

Distance travelled by object per unit time

Question 2

Instantaneous speed

Answer 2

Speed at an instant

Question 3

Distance-time graph

Answer 3

Distance that an object has travelled at different times

Question 4

Uniform motion

Answer 4

Constant speed and fixed direction

Question 5

Non-uniform motion

Answer 5

Changing speed or changing direction

Question 6

Format for trolley’s movement

Answer 6

From time = xxx, the trolley moves at a higher/lower/n.a. steady speed. It is in uniform motion as its speed is constant and direction is unchanged

Question 7

Motion Sensor

Answer 7

Detect the distance of trolley from sensor

Question 8

Force

Answer 8

Push or pull on an objectF

Question 9

Force changes the motion of an object

Answer 9

Faster, slower, start moving, stop, or direction of an object

Question 10

Forces can be measured by

Answer 10

Spring balance –> pulling forces
Motion sensors –> pulling and pushing forces

Question 11

Burger and apple lift

Answer 11

1N

Question 12

Kick a football

Answer 12

150N

Question 13

Launch Saturn V

Answer 13

34 000 000 N

Question 14

Contact forces

Answer 14

Act on object in contact

Question 15

Non-contact forces

Answer 15

Act on object not in contact

Question 16

If motion is at rest or in uniform, force and net force is

Answer 16

Balanced and =0

Question 17

If motion is in non-uniform, force and net force is

Answer 17

Unbalanced force and =/= 0

Question 18

When balanced force act on object at rest

Answer 18

Object stays at rest

Question 19

When balanced force act on moving object

Answer 19

Object is in uniform motion (speed and direction remains the same)

Question 20

When unbalanced forces act on an object

Answer 20

Motion of object changes

Question 21

Force of gravity

Answer 21

2 objects attract each other

Question 22

Force of gravity but exerted by Earth

Answer 22

Exerted by Earth on an object pulls the object towards the Earth’s centre

Question 23

Moon compared with Earth’s gravitational force

Answer 23

Moon exerts force of gravity 1/6 Earth does

Question 24

Correlation between force of gravity and mass

Answer 24

Th greater the mass, the greater the magnitude of the force of gravity acting on object

Question 25

Weight

Answer 25

(N), force of gravity of the Earth acting on the object

Question 26

Mass (kg)

Answer 26

Amount of matter object contains

Question 27

The golden equation of 9.81

Answer 27

Weight = Mass x Constant

Question 28

9.81 is also known as

Answer 28

Ratio of weight to mass

Question 29

Mass with hook, slotted mass

Answer 29

Justhere

Question 30

Mass and weight are directly proportional

Answer 30

Greater mass experiences larger force of gravity and thus greater weight.

Question 31

Friction

Answer 31

The force acting on an object that opposes the object's sliding motion or tendency of sliding motion

Question 32

Overcoming friction by applied force

Answer 32

To start and object moving, there must be an unbalanced force. Once it starts moving, we can go back to a balanced force.

Question 33

Air resistance

Answer 33

When an object moves in air, an opposing force acts on object

Question 34

lubricant answer

Answer 34

The (lubricant) reduces friction between xxx and yyy

Question 35

Air cushion

Answer 35

Friction between two surfaces can be reduced by separating them using a layer of air.

Question 36

Maglev train

Answer 36

Separated from rails by magnetic forces. Friction between them is greatly reduced, train can move at high speeds.

Question 37

Jetfoil

Answer 37

Raised above water. Friction between them is greatly reduced, jetfoil can move at high speeds

Question 38

Air hockey

Answer 38

Separated from table by air cushion

Question 39

Rollers and ball bearings

Answer 39

Allow object to slide or turn more smoothly

Question 40

Streamlined shape

Answer 40

Direct air particles to other directions, thus reducing air restistance

Question 41

Why higher speed, higher air resistance?

Answer 41

The faster an object moves, the more air particles will hit object per unit time.

Question 42

Air resistance at rest or in vacuum.

Answer 42

Negligible.

Question 43

Air resistance depends on 3 factors

Answer 43

Speed Density of fluid Surface area

Question 44

Parachute workings?

Answer 44

Increase air resistance, since more air particles come in contact with parachute.

Question 45

Walking and friction?

Answer 45

Friction between shoes and ground stops foot from slipping backwards. Enable us to walk.

Question 46

Brake and friction?

Answer 46

Brake slows down wheels by friction

Question 47

Anti-slip strips

Answer 47

Increase friction to prevent slipping

Question 48

Friction and holding stuff in place

Answer 48

Friction between climber and rock allows climber to stay safely in place Friction between food and chopsticks allows us to hold food

Question 49

Action-reaction qualities

Answer 49

Opposite direction Same magnitude Different objects

Question 50

Action-reaction style

Answer 50

When (obj) exerts a (direction) force on (obj2), the (obj2) exerts a (opp direction) on (obj) at the same time. These two forces are an action-reaction pair.