Physics - As Fast As You Can

A set of revision cards explaining simple physics formulas. 

HideShow resource information
  • Created by: Elliza
  • Created on: 29-05-11 22:14

Speed and Velocity

To work out velocity, speed, displacement or time taken, use this: (http://kerala.skoool.in/uploadedImages/SpeedTriangle.gif)

  • The 'D' represents 'Displacement'
  • The 'S' represents 'Velocity' or 'Speed' (Both calculations are the same in this case)
  • The 'T' represents 'Time'

Bear in mind that 'm/s' (metres per second) is used for both, speed and velocity. (E.g 40 m/s) However, velocity is a vector quantity, which means it also needs a direction. (E.g 40 m/s North) 


1 of 4

Acceleration

Acceleration is how quickly velocity is changing.

The unit for acceleration is m/s².

To work out acceleration use this:

(http://motivate.maths.org/conferences/conf60/Images/acceleration_formula.gif)

In order to work out the change in velocity, you need to use this: 

Change in velocity = Finishing velocity (m/s) - Initial velocity (m/s)

For example, A skulking cat accelerated from 2m/s to 6m/s in 5.6s. Find it's acceleration.

Answer: Using the formula

Acceleration = (v - u) / t = (6 - 2) / 5.6 = 4 / 5.6 = 0.71 m/s²

'V' represents the finishing velocity, 'U' represents the initial velocity.

2 of 4

Velocity Time Graphs

Here is a typical velocity time graph:

(http://www.physicslearningsite.com/pics/graphs-velocity1.gif)

3 of 4

Velocity Time Graphs Continued...

Things to remember about velocity time graphs:

  • Gradient = Acceleration
  • Flat sections represent steady speed
  • The steeper the graph, the greater the acceleration or deceleration
  • Uphill sections (/) are acceleration
  • Downhill sections (\) are deceleration
  • The area under any section is the distance travelled in that time interval
  • curve means changing acceleration.

(http://png-4.findicons.com/files/icons/1943/yazoo_smilies/128/big_smile.png)

4 of 4

Comments

Alice

it's good but doesn't cover everything

Similar Physics resources:

See all Physics resources »See all Forces and Motion resources »