Topic 1 - Motion

Question 1

2.1 - What is a scalar quantity?

Answer 1

A quantity with a magnitude but no direction.

Question 2

2.2 - What is a vector quantity?

Answer 2

A quantity with both magnitude and direction.

Question 3

2.3 - What are the differences between scalar and vector quantities?

Answer 3

Vector quantities have a direction while scalar quantities only have a magnitude.

Question 4

2.4 - What are some vector and scalar quantities?

Answer 4

Vector - displacement, velocity, acceleration, force, weight, momentum and energy.
Scalar - Distance, speed and mass.

Question 5

2.5 - What is velocity?

Answer 5

Speed in a particular direction.

Question 6

2.6 - What equation links speed, distance and time?

Answer 6

Speed = distance/time
S = d/t

Question 7

2.7 - What are some features of distance/time graphs?

Answer 7

These graphs are used to calculate the speed.
Horizontal lines mean the object is stationary as the distance from the starting point hasn’t changed.
Straight and sloping lines mean the object is travelling at a constant speed.
Steeper the line, faster the object is travelling.
Speed is calculated from the gradient of the line.

Question 8

2.8 - What equation links acceleration, velocity and time?

Answer 8

Acceleration = (final - initial velocity) / time
A = v-u/t

Question 9

2.9 - What equation links velocity, acceleration and distance?

Answer 9

Final velocity squared - initial velocity squared = 2 * acceleration * distance
v^2 - u^2 = 2ax

Question 10

2.10 - What are some features of velocity/time graphs?

Answer 10

Shows changing velocity.
A horizontal line means the object is travelling at constant velocity.
A sloping line up to the right shows the object is accelerating.
A sloping line down to the right shows the object is decelerating.
Steeper the line, greater the acceleration.
Acceleration is calculated from the gradient of the line.
Negative velocity means the object is travelling the opposite direction.
Area under the graph is the distance travelled, it is calculated by velocity*time.

Question 11

2.11 - What are some methods to find speed of objects?

Answer 11

In a laboratory, speed is calculated by measuring distance and time.
For fast objects, light gates are used to measure time as they are more accurate.

Question 12

2.12 - What are some typical speeds found everyday?

Answer 12

Wind - 12 m/s
Sound - 330 m/s
Walking - 1.4 m/s
Running - 5 m/s
Cycling - 6 m/s

Question 13

2.13 - What is the acceleration of an object in free fall?

Answer 13

Acceleration due to gravity is 10 m/s^2.