Physics TOPIC 5 definitions

Question 1

Gravitational force is….. This has 2 effects…

Answer 1

the force of attraction between masses
1 - on surface of planet, it makes all things fall to the ground
2 - it gives everything a weight

Question 2

momentum equation with units

Answer 2

P = mv
kgm/s = kg x m/s

Question 3

force momentum equation

Answer 3

F (N) = mass (kg) x change in velocity (V-U) (m/s)
——————————————-
Change in time (s)

Question 4

momentum is a …. quantity

Answer 4

vector quantity

Question 5

momentum is a property of

Answer 5

all moving objects

Question 6

momentum protection in cars x3

Answer 6

• crumple zone
• seatbelts slightly loosening
• airbags
  all to slow down momentum and reduce force = less injury

Question 7

other momentum safety features in life x2

Answer 7

• foam in bike helmets
• soft/ bouncy flooring in playgrounds

Question 8

Scalar
vector
with egs

Answer 8

• magnitude but no direction ( Mass, Distance, speed, time)
• magnitude and direction
  (Force, Velocity, displacement, weight)

Question 9

All forces are either

Answer 9

contact or non contact.

Question 10

In a closed system, momentum is…. so momentum before…

Answer 10

conserved
= momentum after

Question 11

Mass is… and its not a….. + its measured in

Answer 11

how much matter an object contains
force
KG with a mass balance

Question 12

Weight is…
Its measured in….
Mass and weight are..
measured by a …

Answer 12

The force exerted on a mass by gravity
N
Directly proportional
Newtonmeter

Question 13

Weight equation with units

Answer 13

Weight = Mass x Gravitational field strength.
N = kg x N/Kg

Question 14

Earth + moons gravitational field strength =

Answer 14

earth - 9.8N/kg
Moon - 1.6N/kg

Question 15

forces always come in

Answer 15

pairs

Question 16

centre of mass is….
and this will be the centre of an object if its a …..

Answer 16

• The point at which the mass of an object may be thought of as being concentrated.
• uniform object

Question 17

A vector quantity may be represented by an….
the length represents the …

Answer 17

arrow
magnitude

Question 18

a force is a

Answer 18

push or pull that acts on an object due to the interaction with another object.

Question 19

All forces are either

Answer 19

• contact (friction, air r, tension+ normal contact force)
• non-contact (g force, electrostatic force, magnetic force)

Question 20

Force is a …… quantity

Answer 20

vector

Question 21

When a force causes a displacement of an object, it ……. on it

Answer 21

does work

Question 22

Work done equation

Answer 22

Work done (J) = force (N) x distance (metres) (moved along the line of action of the force)
W = Fs

Question 23

One joule of work is done when…

Answer 23

One newton causes a displacement of one metre
1 joule = 1 newton - 1 metre

Question 24

F = Ke

Answer 24

Force (N) = Spring constant (N/m) x Extension (m)

Question 25

Resultant force is

Answer 25

the single force that represents the sum of all individual forces acting on an object.

Question 26

Hooke's law is

Answer 26

The extension of an elastic object is directly proportional to the force applied, provided its limit of proportionality is not exceeded.

Question 27

Newton's first law is

Answer 27

If the resultant force is zero, a stationary object stays stationary, and a moving object stays at a constant velocity.

Question 28

Newton's second law

Answer 28

F = MA Acceleration is proportional to the resultant force and inversely proportional to mass.

Question 29

Newton's third law

Answer 29

When two objects interact, they exert equal and opposite forces on each other.

Question 30

stopping distance is

Answer 30

the sum of thinking and braking distance.

Question 31

Acceleration is ....

Answer 31

the rate of change of velocity

Question 32

On a Distance time graph, the gradient represents...

Answer 32

speed

Question 33

On a velocity- time graph, the gradient represents

Answer 33

acceleration

Question 34

Inertia is

Answer 34

the tendency for an objects motion to remain unchanged.

Question 35

The speed of running/cycling/ walking depends on factors such as...

Answer 35

- age - terrain - fitness - distance travelled

Question 36

Typical speeds of walking - running - cycling -

Answer 36

walking = 1.5 m/s running = 3 m/s cycling = 6 m/s

Question 37

Typical speed of sound in air is..

Answer 37

330 m/s

Question 38

S = VT

Answer 38

distance travelled (m) = speed (m/s) x time (s)

Question 39

Velocity definition

Answer 39

The velocity of an object is its speed in a given direction.

Question 40

Motion in a circle involves

Answer 40

constant speed but changing velocity (bc its a vector and direction is constantly changing)