P8 - 11

Question 1

vector

Answer 1

Magnitude and direction

Question 2

Scalar

Answer 2

Just a magnitude

Question 3

Examples of scalar variables

Answer 3

Speed, distance, time, mass, energy

Question 4

Examples of vector variables

Answer 4

Velocity, displacement, acceleration, force, momentum

Question 5

Define force

Answer 5

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

Question 6

Non contact forces

Answer 6

Electrostatic, gravitational attraction, magnetic, nuclear

Question 7

Contact forces

Answer 7

Friction, tension, air resistance, upthrust, thrust, normal reaction force

Question 8

What is the formula for weight

Answer 8

Weight = mass x gravitational field strength

Question 9

What is the formula for work

Answer 9

Work done = force x distance

Question 10

What is elastic deformation

Answer 10

Object returns to its original shape when the load has been removed ( an elastic band )

Question 11

What is plastic deformation

Answer 11

The object does not return to its original shape when the load has been removed ( a spring that has been pulled too far )

Question 12

What is Hooke’s law

Answer 12

The extension of an elastic object, such as a spring, is directly proportional to the force applied, provided that the limit of proportionality is not exceeded

Question 13

What is the equation for Hooke’s law

Answer 13

F = kx ( force (N) = spring constant (Nm^-1) x extension (m)

Question 14

What is the formula for work done on a spring

Answer 14

Work done = 1/2 x k (spring constant) x x^2 (extension)

Question 15

What is the formula for moment of a force

Answer 15

Moment of a force = force x perpendicular distance ( M = F x d )

Question 16

What is equilibrium in moments

Answer 16

Sum of anticlockwise moments = sum of clockwise moment

Question 17

What happens when a bike is using a smaller gear

Answer 17

Faster movement with less force being applied

Question 18

What happens when a bike is using a larger gear

Answer 18

Slower turning with more force being applied

Question 19

What is the formula for pressure

Answer 19

P = F/A ( pressure = force / area )

Question 20

How can an object float

Answer 20

If the object’s weight is less than the weight of the water it displaces

Question 21

What is the formula for pressure due to a column of liquid

Answer 21

Pressure = height of column x density of liquid x gravitational field strength ( p = hpg )

Question 22

What is distance

Answer 22

How far an object moves, not involving direction

Question 23

What is displacement

Answer 23

Both the distance an object moves, measured in a straight line from the start point to the finish point, and the direction of that straight line

Question 24

What is the difference between speed and velocity

Answer 24

Speed has no direction included, velocity includes a given direction

Question 25

What is the formula for average speed

Answer 25

Average speed = total distance / total time

Question 26

Displacement-time graphs

Answer 26

- Gradient is velocity - sharper gradient means faster speed - curved line means changing velocity (acceleration) - if an object is accelerating, its speed can be determined by drawing a tangent and calculating the gradient of the graph

Question 27

Velocity-time graphs

Answer 27

- gradient is acceleration - sharper gradient means greater acceleration - area under line = distance travelled

Question 28

What is Newtons first law

Answer 28

An object has constant velocity unless acted upon by a resultant force

Question 29

What is Newtons second law

Answer 29

The acceleration of an object is proportional to the resultant force acting on the object, and inversely proportional to the mass of the object

Question 30

What is Newtons third law

Answer 30

Whenever 2 objects interact, the forces they exert on each other are equal and opposite

Question 31

What is the formula for Force ( speed context )

Answer 31

Mass x acceleration ( F = ma )

Question 32

What is the formula for inertial mass

Answer 32

Force / acceleration ( f / a )

Question 33

What is inertia

Answer 33

The measure of how difficult it is to change the velocity of an object

Question 34

What is the formula for stopping distance

Answer 34

Thinking distance + braking distance

Question 35

What conditions affect braking distance

Answer 35

- speed - poor road conditions ( icy, wet ) - bald tires ( low friction ) - worn brake pads - weight ( more passengers )

Question 36

What conditions affect thinking distance

Answer 36

- speed - reaction time - concentration - tiredness - distractions - influence of drugs/alcohol

Question 37

What is the formula for momentum

Answer 37

Momentum = mass x velocity ( p = m x v )

Question 38

What is the formula for force ( momentum context )

Answer 38

Force = change in momentum / time = (mv - mu) / t

Question 39

Safety features in cars

Answer 39

Seatbelts ( stretching increases distance moved slightly but extends the time taken before the passenger stops. Decreases the rate of change of momentum reducing the force ) Crumple zones ( 'softens' the blow of a crash. Absorbs energy to deform and compact. Increases time taken for the car to stop. Reduces acceleration and force on passengers ) Air bags ( increases time taken for the passengers head to stop moving, reducing the force on the neck )