## Wednesday, March 16, 2011

### Physics Form 4: Chapter 2 -Graph of Motion

Displacement-Time Graph:

• Gradient of the graph is equal to velocity
• Gradient = 0 , velocity = 0.
• Gradient is negative and constant, hence velocity is uniform and in opposite direction.
• Gradient is increasing, hence velocity is increasing.

Velocity-Time Graph:

•  The gradient of the velocity-time graph gives acceleration.
• Gradient = 0, hence velocity is constant but acceleration = 0.
• The area below the velocity-time graph gives a value of the object's displacement.

Click on the diagram below to play!

Anonymous said...

Cikgu Wong, can you help me to solve this question.

In emergency stop, a driver applies the breaks in a car travelling at 24 ms-1. The car stops after travelling 19.2m while braking. Calculate the average acceleration of the car during braking?

cikgu wong said...

Initial velocity, u = 24
Final velocity, v = 0
Total distance, s = 19.2

Use V2= U2 + 2as formula
0 = 576 + 2a(19.2)
a = -576/19.2 = 30 ms-2

Anonymous said...

Thank you cikgu wong

siti aisyah said...

im always confuse when i want to use the formula..which formula shouls i use .can you help me and teach me how to use formula based on the question

Manisha Majid said...

cikgu wong , why don't you just use this formula , v-u/t , for the first question in the comments ?

Anonymous said...

Manisha, it is because, there is no time required in the question. so you cannot use the formula v-u/t.