Module 3-Forces and Motion

Question 1

What is displacement and how does it differ from distance

Answer 1

Distance is the ground covered regardless of the direction
Whereas displacement only account for the change in position
In relation to the starting point

Question 2

What do you know about displacement time graphs

Answer 2

Displacement goes on the y
Time goes on the x
Velocity is the gradient

Question 3

What do you know about velocity time graphs

Answer 3

Velocity goes on y
Time goes on x
Acceleration is gradient
Displacement is area under the graph

Question 4

State the SUVAT equation that beggins with v^2

Answer 4

v^2=u^2+2as

Question 5

What is the SUVAT equation that begins in v

Answer 5

v=u+at

Question 6

1/2(u+v)t= what

Answer 6

s

Question 7

SUVAT equation-S is equal to what (both)

Answer 7

S=ut+1/2at^2
S=vt-1/2at^2

Question 8

What is the equation for stopping distance

Answer 8

Stopping distance=thinking distance+braking distance

Question 9

How does an object reach it’s terminal velocity

Answer 9

An object in free fall will accelerate at first as the drag is smaller than the weight
However as the object speeds up, the drag increases at the same rate
This causes the forces of drag and weight to balance out
At which point the object will stay at a constant velocity as there are no net forces to change it.

Question 10

What is the equation that links force mass and acceleration

Answer 10

Force = mass x acceleration

Question 11

What is centre of mass

Answer 11

Centre of mass is an imaginary point where all of the mass can be considered to be at one point

Question 12

What is centre of gravity

Answer 12

Centre of gravity is the point directly underneath the centre of mass where the whole weight acts upon

Question 13

What is drag

Answer 13

Drag is the force experienced on an object moving through a fluid opposite to the direction of motion

Question 14

What is the equation for a moment

Answer 14

Moment = perpendicular force x distance to pivot

Question 15

What is a couple

Answer 15

A couple (of torques) is a pair of rotational forces that act on the same object together spinning it without overall movement e.g. two forces on bike pedals

Question 16

What is the equation for pressure

Answer 16

Pressure = force / area

Question 17

What is the equation for density

Answer 17

Density = mass / volume

Question 18

What is the equation for pressure of a liquid

Answer 18

Pressure= height (column of liquid) x density x gravitational pull

Question 19

What is the equation linking work done force and distance

Answer 19

Work done = force x distance (in the direction of work)

Question 20

What is the principle of conservation of energy

Answer 20

Energy cannot be created nor destroyed

Question 21

What are the 8 types of energy

Answer 21

Kinetic
Gravitational potential
Electrical potential
Elastic potential
Chemical
Nuclear
Electromagnetic
Thermal (internal)

Question 22

Define power and state equation

Answer 22

Power is force applied in a short time and therefore the equation is power = work done / time

Question 23

What is the equation for efficiency

Answer 23

Efficiency = useful power output/total power input x 100%

Question 24

What is a tensile and compressive force

Answer 24

A force that pulls an object in two opposite ways (tensile)
A force that pushes an object towards its centre (compressive)

Question 25

What is the name given when an object changes shape and doesn’t return to its original form

Answer 25

Deformation

Question 26

What is elastic potential energy

Answer 26

It is the energy stored up in an object when it is stretched or squashed and wants to return to its original shape

Question 27

What is elastic and plastic deformation

Answer 27

Elastic deformation is when an object can change back to its original shape Plastic deformation is when an object exceeds its elastic limit and cannot return to its original shape

Question 28

What is the equation for tensile stress

Answer 28

Tensile stress=force / area

Question 29

What is the equation for tensile strain

Answer 29

Tensile strain = extension / original length

Question 30

What is young modulus

Answer 30

Young modulus is the gradient of the stress vs strain graph and put simply is the stiffness of a material-the higher the young modulus the stiffer the material will be

Question 31

Does young modulus change with size, shape or width

Answer 31

None! Young modulus of an object is only dependent on the material itself

Question 32

What is Newton’s first law of motion

Answer 32

An object will remain at rest or continue at a constant velocity as long as no resultant force acts upon it

Question 33

What is Newton’s second law

Answer 33

The resultant force acting on an object is proportional to the rate of change of momentum

Question 34

What is Newton’s third law

Answer 34

If object A exerts a force on object B, object B will exert an equal and opposite force on object A and the forces are the same type and in the same line of motion

Question 35

What is the significance of change of momentum when relating to force

Answer 35

The faster the change in momentum occurs, the larger the force.

Question 36

What is an impulse

Answer 36

An impulse is the change in momentum for example you experience a high impulse when going on a rollercoaster

Question 37

What are two quantities that are conserved in all collisions

Answer 37

Energy Linear momentum

Question 38

What is the UTS of a material

Answer 38

The max amount of tensile stress it can take before it breaks