linear motion

Question 1

Distance VS displacement

Answer 1

Distance is the total length travelled by an object irrespective of the direction of motion
- scalar quantity

Displacement is the linear distance from a fixed position in a specified direction
- vector quantity (both magnitude & direction)

Both SI unit is metre (m)

Question 2

Define speed

Answer 2

Speed is the rate of change of distance travelled

Scalar quantity

SI unit - metres per second (ms⁻¹)

|v| = |dx/dt|

Question 3

Define velocity

Answer 3

Velocity is the rate of change of displacement

Vector quantity (acts in the direction of displacement)

SI unit - metres per second (ms⁻¹)

v = ds/dt

Question 4

Define acceleration

Answer 4

Acceleration is the rate of change of velocity

Vector quantity (acting in the direction of the change of velocity - an object is said to be accelerating if its velocity is changing, either in magnitude or direction)

SI unit - metres per second (ms⁻²)

a = dv/dt

Question 5

With reference to a velocity time graph, what information are we able to derive?

Answer 5

Axes - velocity of an object at any point in time

Gradient - rate of change of velocity (instnataneous acceleration)

Area under graph - change in displacement

Question 6

What are the 4 equations of SUVAT?

Answer 6

check the notes i lazy type out

Question 7

What is Newtons 3rd Law of motion?

Answer 7

The force exerted on one body by another is equal in magnitude and opposite in direction to the force simultaneouslty exerted

Force on 1st body by 2nd body = - Force on 2nd body by first body

Question 8

What are the 4 conditions for forces to be an action reaction pair?

Answer 8

1. The 2 forces act on different bodies
2. The forces are equal in magnitude
3. They forces must be the same type of force (contact / non-contact)
4. The forces must be opposite in direction

Question 9

Define Linear momentum

Answer 9

The product of its mass and velocity

p = mv

Question 10

What is Newtons 2nd law of motion?

Answer 10

The rate of change of momentum of a body is directly proportional to the external resultant force acting on the body and is in the same direction as the external force.

dp/dt ∝ ΣF external

Question 11

What is Newtons 1st law of motion?

Answer 11

A body at rest will stay at rest and a body in motion will continue to move at a constant velocity, unless acted on by a resultant external force

aka the law of intertia