Forces And Motion

Question 1

What is speed defined as?

Answer 1

The distance travelled per unit time

Speed is a scalar quantity.

Question 2

What does it mean if the speed of something is changing?

Answer 2

It is accelerating or decelerating

Acceleration is a change in speed over time.

Question 3

What is the formula for average speed?

Answer 3

average speed = total distance / total time

This formula calculates the mean speed over a specific distance.

Question 4

What is velocity?

Answer 4

The speed in a given direction

Velocity is a vector quantity.

Question 5

What is acceleration?

Answer 5

The change in velocity per unit time

Acceleration can be positive (speeding up) or negative (slowing down).

Question 6

What is the formula for acceleration?

Answer 6

acceleration = change in velocity / time

It can also be expressed as a = (final speed - initial speed) / time.

Question 7

What is the equation relating final speed, initial speed, acceleration, and distance?

Answer 7

(final speed)² = (initial speed)² + (2 × acceleration × distance)

This equation is useful in kinematic calculations.

Question 8

In which units is distance measured?

Answer 8

Metres (m)

Distance is a scalar quantity.

Question 9

In which units is time measured?

Answer 9

Seconds (s)

Time is a scalar quantity.

Question 10

In which units is speed and velocity measured?

Answer 10

Metres per second (m/s)

Both are scalar and vector quantities, respectively.

Question 11

In which units is acceleration measured?

Answer 11

Metres per second squared (m/s²)

Acceleration indicates how quickly velocity changes.

Question 12

What does a gradient represent in a displacement-time graph?

Answer 12

Velocity

The steepness of the gradient indicates the speed of the object.

Question 13

What does a negative gradient in a displacement-time graph indicate?

Answer 13

Returning back to the starting point

This indicates a change in direction.

Question 14

What does a horizontal line in a displacement-time graph mean?

Answer 14

It is stationary

No displacement means no movement.

Question 15

What does a curved line in a displacement-time graph indicate?

Answer 15

The velocity is changing (accelerating/decelerating)

The curvature reflects a non-constant speed.

Question 16

What does the gradient represent in a velocity-time graph?

Answer 16

Acceleration

The steeper the gradient, the greater the acceleration.

Question 17

What does a negative gradient in a velocity-time graph indicate?

Answer 17

Deceleration

This shows a reduction in speed over time.

Question 18

What does a horizontal line in a velocity-time graph mean?

Answer 18

Constant speed

The object travels at the same speed throughout the time interval.

Question 19

What does the area under the line in a velocity-time graph represent?

Answer 19

The distance travelled

This is useful for calculating total distance from speed over time.

Question 20

What does a curved line in a velocity-time graph indicate?

Answer 20

The acceleration is changing

The curvature reflects a non-constant acceleration.

Question 21

Fill in the blank: If the speed is zero, it is _______.

Answer 21

at rest

This indicates no movement.

Question 22

What is the difference between a vector and a scalar?

Answer 22

A vector has magnitude and direction; a scalar has just a magnitude.

Question 23

Give examples of scalars.

Answer 23

• Distance
• Speed
• Time
• Energy

Question 24

Give examples of vectors.

Answer 24

• Displacement
• Velocity
• Acceleration
• Force

Question 25

What can forces change in a body?

Answer 25

Forces can change the speed, shape or direction of a body.

Question 26

In what unit are forces measured?

Answer 26

Newtons (N)

Question 27

What is friction?

Answer 27

Friction is a force between two surfaces which impedes motion and results in heating.

Question 28

What is air resistance?

Answer 28

Air resistance is a form of friction.

Question 29

How do you find the resultant of two or more forces acting along the same line?

Answer 29

Add them together if in the same direction and subtract if in the opposite direction.

Question 30

State Newton's first law.

Answer 30

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

Question 31

State Newton's second law.

Answer 31

Force = mass X acceleration (F = ma).

Question 32

What is mass?

Answer 32

Mass is a measure of how much matter is in an object, measured in kilograms (kg).

Question 33

What is weight?

Answer 33

Weight is a gravitational force, the effect of a gravitational field on a mass.

Question 34

What is the equation for weight?

Answer 34

weight = mass X gravitational field strength.

Question 35

What is the gravitational field strength on Earth?

Answer 35

10 N/kg.

Question 36

How do you calculate weight using gravitational field strength?

Answer 36

W = mg.

Question 37

What happens to a body falling in a uniform gravitational field initially?

Answer 37

Initially, there is no air resistance and the only force acting on it is weight.

Question 38

What occurs as a body falls in a gravitational field?

Answer 38

It accelerates, increasing its speed and hence air resistance.

Question 39

What happens to the resultant force as a body accelerates in a gravitational field?

Answer 39

The resultant force downwards decreases.

Question 40

What happens when the air resistance equals the weight of the falling body?

Answer 40

There is no resultant force, so there is no acceleration and terminal velocity is reached.

Question 41

What is the force applied to a spring called in Hooke's law?

Answer 41

F ## Footnote F represents the force applied to the spring.

Question 42

What does 'k' represent in Hooke's law?

Answer 42

Spring constant ## Footnote 'k' is a measure of the stiffness of the spring.

Question 43

What is the distance travelled before a driver applies the brakes called?

Answer 43

Thinking distance ## Footnote Thinking distance increases with greater speed and slower reaction times.

Question 44

What factors can increase thinking distance?

Answer 44

* Greater speed * Slower reaction time due to alcohol, tiredness, or distractions * Caffeine reduces thinking distance ## Footnote Caffeine affects reaction time positively.

Question 45

What is the distance travelled from pressing the brakes to the vehicle stopping called?

Answer 45

Braking distance ## Footnote Braking distance can be affected by speed, mass, and road conditions.

Question 46

What factors can increase braking distance?

Answer 46

* Greater speed or mass * Poor road conditions (icy, wet) * Car conditions (worn tires, worn brake pads) ## Footnote These factors can significantly affect stopping performance.

Question 47

What is the formula for calculating the stopping distance?

Answer 47

Stopping distance = Thinking distance + Braking distance ## Footnote This represents the total distance a vehicle travels before coming to a stop.

Question 48

What is deformation in the context of forces?

Answer 48

Change in size and shape of a body ## Footnote Deformation can be elastic or plastic depending on the material's response to the applied force.

Question 49

What is elastic deformation?

Answer 49

Object returns to its original shape when load is removed ## Footnote An example is a spring being stretched under normal usage.

Question 50

What is the limit of proportionality?

Answer 50

Point where the force-extension graph stops being linear ## Footnote Beyond this point, the material does not obey Hooke's law.

Question 51

What does the gradient of the force-extension graph represent?

Answer 51

Spring constant, k ## Footnote The steeper the gradient, the stiffer the spring.

Question 52

True or False: A non-linear force-extension graph indicates deformation that follows Hooke's law.

Answer 52

False ## Footnote Non-linear graphs indicate deformation that does not follow Hooke's law.

Question 53

What occurs in the plastic region of a force-extension graph?

Answer 53

Permanent deformation occurs ## Footnote After this region, the material will likely fracture.

Question 54

What is the relationship defined by Hooke's law?

Answer 54

F = kx ## Footnote This relationship describes how the force applied to a spring relates to its extension.

Question 55

Hookes law definition

Answer 55

if you apply a force to a spring, then the force stretches spring. And if you don't stretch too much, Hooke's law says that the amount of force you apply is proportional to the stretch. So, that means that if you apply twice the force, you get twice the stretch.

Question 56

Scalar quantity

Answer 56

Only have a magnitude (size)

Question 57

Vector quantity

Answer 57

Have direction and magnitude

Question 58

Vector quantity

Answer 58

Have direction and magnitude