Forces

Question 1

What is the difference between scaler and vector ?

Answer 1

Speed and distance are scalar : have only magnitude

Displacement and velocity are vector : have direction and magnitude

Question 2

Explain what a non contact force is ?

Answer 2

When objects are physically separated ?

Question 3

Formula for weight ?

Answer 3

Mass x gravitational field strength

Question 4

What is the rule for gravity ( attraction ) ?

Answer 4

The larger the mass, the stronger the field , the greater the attraction

Question 5

Definition of resultant force ?

Answer 5

A single force representing the sum of all forces acting on an object

Question 6

Formula for work done ?

Answer 6

Work done = Force x distance

Question 7

Explain Hooke’s law ?

Answer 7

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 8

What is the difference between distance and displacement ?

Answer 8

Distance = how far an object moves. Does not involve direction. ( Scaler quantity )
Displacement = includes both the distance from the start point to finish point, as well as distance travelled. ( Vector quantity )

Question 9

What is the difference between speed and velocity ?

Answer 9

Speed = does not involve direction ( scaler )
Velocity = speed in a given direction ( vector )

Question 10

What is Newtons first law ?

Answer 10

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

Question 11

What is Newtons second law ?

Answer 11

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 12

Formula for force ?

Answer 12

Force = mass x acceleration ( F = ma )

Question 13

What is the definition of Inertia ?

Answer 13

The measure of how difficult it is to change the velocity of an object. Objects will remain in their existing state of motion unless acted upon by an unbalanced force

Question 14

Formula for Inertial mass ?

Answer 14

Inertial mass = force / acceleration = f /a

Question 15

What is Newtons third law ?

Answer 15

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

• Every action has an equal and opposite force

Question 16

Definition of reaction time ?

Answer 16

Time taken for driver to react in an emergency and mov their feet from the accelerator pedal to the brake pedal

Question 17

Definition of thinking distance ?

Answer 17

Distance travelled by vehicle during reaction time (continues to move at a constant speed in this time)

Question 18

Definition of braking distance ?

Answer 18

Distance a vehicle travels whilst it is stopped by the brakes

Question 19

How do you calculate the stopping distance ?

Answer 19

Thinking distance + braking distance

Question 20

Factor affecting the thinking distance ?

Answer 20

Speed
Concentration
Tiredness
Distractions
Influence of alcohol/drugs

Question 21

Factors affecting braking distance ?

Answer 21

Speed
Poor road conditions ( icy, wet)
Bald tires ( low friction )
Worn brake pads
Weight ( more passengers )

Question 22

Formula for momentum ?

Answer 22

Momentum = mass x velocity ( P = mv )

*As velocity is a vector quantity, so is momentum

Question 23

Definition of Conservation of momentum ?

Answer 23

When two objects collide, their total momentum before the collision equals their total momentum after the collision, providing theyre in a closed system with no external forces acting upon the objects

Question 24

Definition of air resistance ?

Answer 24

This is the force that acts against gravity on a falling object. This makes different objects fall at different rates.

Question 25

Definition of terminal velocity ?

Answer 25

When an object moves at it’s maximum possible Speed