5.3 Linear Motion

Question 1

Scalar quantity + vector quantity

Answer 1

Scalar = when measurements are described only in terms of size or magnitude - mass, distance, speed.
Vector = when measurements are described in terms of magnitude + direction - weight, acceleration, displacement, velocity + momentum.

Question 2

Distance time graphs

Answer 2

• If line goes straight horizontally across means no distance has been travelled.
• If curve starts to level off less distance is travelled in a certain amount of time
• If line goes up in a constant diagonal direction indicates distance run is changing at a constant rate and at same speed
• Curved line gradually gets steeper indicates more distance is travelled in a certain amount of time

Question 3

Velocity time Graphs

Answer 3

Above x axis = acceleration
Downward line into x axis = deceleration
Below x axis = changing direction

Question 4

Forces acting upon linear motion

Answer 4

• External forces = comes from outside the body. I.e. friction, air resistance, weight + gravity.
• internal forces = generated by the skeletal muscles. I.e quadricep contracting alongside other leg muscles forcing us to run

Question 5

Impulse

Answer 5

= force x time
- momentum = mass x velocity
Start of race = less neg, more pos (accelerating)
Middle race = equal neg + pos (constant speed)
End of race = more neg, less pos (decelerating)