Forces and Motion

Question 1

Accelerate

Answer 1

increase in speed or velocity

Question 2

balanced forces

Answer 2

forces with equal size but opposite direction acting on a single object. they cancel out, and are equivalent to no force at all.

Question 3

collision damage

Answer 3

the damage caused to an object when it collides with another object

Question 4

conserved

Answer 4

has the same value before and after an event (such as a collision)

Question 5

elastic collision

Answer 5

a collision in which the total kinetic energy of the objects before and after they collide is the same.

Question 6

external forces

Answer 6

forces that are not directly involved in a collision or explosion. for example, air resistance and wind force

Question 7

kinetic energy

Answer 7

movement energy. depends on the mass and speed of an object - not its velocity. measured in joules (J)

Question 8

momentum

Answer 8

a measure of an objects ability to cause damage when it collides with another object. Depends on the objects mass and velocity

Question 9

newtons third law

Answer 9

when two objects collide, they exert equal but opposite forces on one another these forces are newton pairs.

Question 10

action force

Answer 10

the force one object exerts on another object during a collision. opposite to the reaction force.

Question 11

collide

Answer 11

bump into

Question 12

conservation of momentum

Answer 12

the total momentum before and after a collision/explosion is always the same, if no external forces act.

Question 13

contact time

Answer 13

the time during which two colliding objects exert forces on each other.

Question 14

explosion

Answer 14

one or more stationary objects breaking apart then moving away in opposite directions, with an increase in kinetic energy.

Question 15

inelastic collision

Answer 15

a collision in which the total kinetic energy of the colliding objects decreases during the collision.

Question 16

mass

Answer 16

the amount of material in an object measured in kilograms

Question 17

newton pairs

Answer 17

a pair of forces acting on two colliding objects. the forces have the same size but act in opposite directions, one force on each object.

Question 18

potential energy

Answer 18

stored energy. measured in joules (J)

Question 19

rate of change

Answer 19

a measure of how much a quantity changes in a given time

Question 20

reaction force

Answer 20

the force one object exerts on another object during a collision. Opposite to the action force

Question 21

rest

Answer 21

not moving

Question 22

scalar quantity

Answer 22

a quantity that only has a magnitude no direction. for example speed.

Question 23

stationary

Answer 23

not moving

Question 24

vector quantity

Answer 24

a quantity that has both a magnitude and a specific direction. for example velocity

Question 25

safety features

Answer 25

properties of a vehicle or object designed to minimise the damage it can cause during a collision.

Question 26

speed

Answer 26

the distance travelled in one second. measured in metres per second. (m/s)

Question 27

unbalanced forces

Answer 27

two or more forces acting on a single object that do not cancel out.

Question 28

velocity

Answer 28

speed in a specific direction