Mechanics

Question 1

Scalars

Answer 1

Have only magnitude
e.g distance speed mass energy power

Question 2

Vectors

Answer 2

Have magnitude and direction
e.g displacement velocity acceleration force weight momentum

Question 3

Adding vectors

Answer 3

R=-/x² + y²

Question 4

Displacement-Time graph

Answer 4

X=time
Y=displacement
M=velocity

Question 5

Velocity-Time graph

Answer 5

X=time
Y=velocity
M=acceleration
Area=displacement

Question 6

Acceleration-Time graph

Answer 6

X=time
Y=acceleration
Area=change in velocity

Question 7

Conservation of momentum

Answer 7

Total momentum before collision=Total momentum after collision

Question 8

Impulse

Answer 8

Change in momentum
Impulse=F^t=^(mv)

Question 9

Momentum in Newton’s 2nd Law

Answer 9

Force= rate of change of momentum
F=^(mv)/^t

Question 10

Force-Time graph

Answer 10

X=time
Y=force
Area=impulse

Question 11

Moment of a force

Answer 11

Moment of force about a point= force × perpendicular distance from the point to the line of action of the force

Question 12

Couple

Answer 12

A pair of equal and opposite coplanar forces

Question 13

Principle of Moments

Answer 13

Sum of clockwise moments = Sum of anticlockwise moments

Question 14

Newton’s 1st Law

Answer 14

An object will remain at rest or constant velocity unless acted upon by a net force

Question 15

Newton’s 2nd Law

Answer 15

The resultant force acting on an object is equal to its mass multiplied by its acceleration (F=ma)

Question 16

Newton’s 3rd Law

Answer 16

When object A exerts a force on object B, object B exerts a force equal magnitude on object A in the opposite direction
THE FORCES MUST BE THE SAME TYPE OF FORCE AND ON DIFFENT OBJECTS

Question 17

Mass

Answer 17

The amount of matter in an object

Question 18

Weight

Answer 18

The gravitational force that an object experiences due to its mass

Question 19

Acceleration due to gravity

Answer 19

All objects accelerate at the same rate in a uniform gravitational field regardless of the mass of the object
(ignoring air resistance)

Question 20

Centre of Mass

Answer 20

The point from which an object’s weight can be considered to act through

Question 21

Frictional Forces

Answer 21

Forces that oppose motion (act in opposite direction)
Frictional forces convert kinetic energy into heat and sound energy

Question 22

Terminal Speed

Answer 22

The maximum speed that can be reached by an object experiencing frictional forces

Question 23

Work

Answer 23

The amount of energy transferred from one form to another

Question 24

Power

Answer 24

The rate of doing work
The rate of energy transfer

Question 25

Force-Displacement graph

Answer 25

X=displacement Y=force Area=work done

Question 26

Principle of Conversation of Energy

Answer 26

Energy can not be created or destroyed - it is transferred from one form to another

Question 27

Inelastic Collisions

Answer 27

Kinetic energy is NOT conserved

Question 28

Elastic Collisions

Answer 28

Kinetic energy IS conserved

Question 29

Energy changes: Explosions

Answer 29

Energy (usually chemical) converted to kinetic energy

Question 30

Energy changes: Elastic Deformation

Answer 30

Work done to stretch the material, giving it elastic strain energy Elastic strain energy converted back to kinetic energy when material released

Question 31

Energy changes: Plastic Deformation

Answer 31

Work is done to deform the material, releasing heat energy This energy will NOT be converted back to kinetic energy or GPE

Question 32

Vehicle safety

Answer 32

Energy: The energy transferred to a passenger in a collision can be reduced by converting some of the KE into other forms (using KE to plastically deform crumple zones) Force: The force that a passenger experiences during a crash can be reduced by extending the time over which the collision occurs (F=^(mv)/^t