Unit 3.1

Question 1

What is the difference between a scalar quantity and a vector quantity?

Answer 1

A scalar quantity is specified by magnitude alone, while a vector quantity is specified by both magnitude and direction.

Question 2

Give an example of a scalar quantity.

Answer 2

Mass, which is measured in kilograms and has only magnitude.

Question 3

Give an example of a vector quantity.

Answer 3

Force, which has both magnitude and direction.

Question 4

What is the acceleration due to gravity commonly represented as?

Answer 4

g, with a value of -9.8 m s-2.

Question 5

What does negative acceleration indicate?

Answer 5

It indicates that an object is slowing down, also known as deceleration.

Question 6

What are the three equations of motion for constant acceleration?

Answer 6

v = u + at,

s = ut + 1/2 at²,

v² = u² + 2as.

Question 7

What does ‘u’ represent in the equations of motion?

Answer 7

Initial velocity measured in metres per second (m s-1).

Question 8

What does ‘v’ represent in the equations of motion?

Answer 8

Final velocity after time t measured in metres per second (m s-1).

Question 9

What does ‘a’ represent in the equations of motion?

Answer 9

Acceleration during time t measured in metres per second squared (m s-2).

Question 10

What does ‘s’ represent in the equations of motion?

Answer 10

Displacement during time t measured in metres (m).

Question 11

What does ‘t’ represent in the equations of motion?

Answer 11

Time over which acceleration occurs measured in seconds (s).

Question 12

How is displacement calculated for an object showing uniform acceleration?

Answer 12

Displacement can be calculated from the product of average velocity and time.

Question 13

What is the formula for average velocity?

Answer 13

Average velocity = (u + v) / 2.

Question 14

What is the relationship between distance and average speed?

Answer 14

Distance = average speed × time (scalar).

Question 15

What is the relationship between displacement and average velocity?

Answer 15

Displacement = average velocity × time (vector).

Question 16

What is the initial velocity of an object that is dropped?

Answer 16

0 m s-1.

Question 17

What happens to the velocity of an object thrown upwards at its maximum height?

Answer 17

The velocity is 0 m s-1.

Question 18

How do you indicate opposite directions in vector quantities?

Answer 18

By assigning a positive or negative value to the magnitude.

Question 19

What is the effect of friction in motion problems involving gravity?

Answer 19

The effects of friction are usually ignored in calculations.

Question 20

What is the maximum height reached by a ball thrown into the air with a velocity of 6 m s-1?

Answer 20

The maximum height can be calculated using the equations of motion.

Question 21

How do you approach solving equations of motion problems?

Answer 21

List the variables u, v, a, s, and t, and decide on positive and negative directions.

Question 22

What is the formula for calculating time to reach maximum height for a projectile?

Answer 22

t = (v - u) / a, where v is final velocity, u is initial velocity, and a is acceleration.

Question 23

What is the displacement of an object returning to its starting position?

Answer 23

The displacement is zero.

Question 24

What is the typical convention for vertical motion in physics?

Answer 24

Upward motion is positive, and downward motion is negative.

Question 25

What is the significance of the negative sign in acceleration due to gravity?

Answer 25

It indicates that gravity always acts downwards.

Question 26

What is the formula for calculating displacement when an object is thrown upwards?

Answer 26

s = ut + 1/2 at², where a is negative due to gravity.

Question 27

What is the horizontal motion of a projectile independent of?

Answer 27

The vertical motion of the projectile.

Question 28

What causes vertical acceleration in projectile motion?

Answer 28

Acceleration due to gravity.

Question 29

How does horizontal motion behave in projectile motion?

Answer 29

The object travels with a constant velocity.

Question 30

What equation is used for horizontal motion in projectile motion?

Answer 30

s = vt (distance = velocity x time).

Question 31

What is the initial vertical velocity of a projectile when it is launched horizontally?

Answer 31

0 m/s.

Question 32

What must be considered independently in projectile motion?

Answer 32

Horizontal and vertical motion.

Question 33

How do you find the time of flight in projectile motion?

Answer 33

Calculate time using horizontal motion and apply it to vertical motion.

Question 34

If a ball lands 0.80 m from the base of the table, what is the time of flight?

Answer 34

0.53 seconds.

Question 35

What is the formula for vertical motion in projectile motion?

Answer 35

s = ut + 0.5at².

Question 36

How do you resolve a vector into its components?

Answer 36

By forming a right-angled triangle.

Question 37

What is the formula for the vertical component of velocity at an angle?

Answer 37

v_vertical = v * sin(θ).

Question 38

What is the formula for the horizontal component of velocity at an angle?

Answer 38

v_horizontal = v * cos(θ).

Question 39

What happens to the vertical component of velocity at maximum height?

Answer 39

It becomes 0 m/s.

Question 40

What is the range of a projectile?

Answer 40

The horizontal distance traveled before landing.

Question 41

What is the vertical component of a projectile launched at 25 m/s at 30°?

Answer 41

12.5 m/s.

Question 42

What is the horizontal component of a projectile launched at 25 m/s at 30°?

Answer 42

21.7 m/s.

Question 43

What does a velocity-time graph indicate about acceleration?

Answer 43

The gradient of the graph gives the value of acceleration.

Question 44

What does a positive slope on a velocity-time graph indicate?

Answer 44

Uniform positive acceleration.

Question 45

What does a negative slope on a velocity-time graph indicate?

Answer 45

Uniform negative acceleration.

Question 46

How can displacement be calculated from a velocity-time graph?

Answer 46

By calculating the area under the graph.

Question 47

What is the relationship between the two halves of a projectile's flight?

Answer 47

They mirror each other.

Question 48

What is the effect of air resistance on projectile motion?

Answer 48

It can reduce the range and alter the trajectory.

Question 49

What is the significance of the vertical velocity being negative during descent?

Answer 49

It indicates the direction of motion is downward.

Question 50

What is the acceleration due to gravity used in calculations?

Answer 50

Approximately 9.8 m/s².

Question 51

What does the term 'resultant velocity' refer to in projectile motion?

Answer 51

The combined effect of horizontal and vertical components.

Question 52

What is the importance of resolving vectors in projectile motion problems?

Answer 52

It allows for separate calculations of horizontal and vertical motions.