It means that Vy(t)=Vy(t=0)+a*t =Vy(t=0)-g*t

The average speed from 0 to t is equal to

(V(t=0)+V(t))/2= V(t=0)+a*t/2= V(t=0)-g*t/2

because velocity change linearly.

So the distance traveled in y direction= average speed * t = V(t=0)*t - gt

^{2}/2

The distance traveled in x direction is Vx*t because velocity did not change in the horizontal direction.

This applet let you play with projectile.

You can adjust the initial (x,y) position of particle with mouse.

Drag the red arrow to change the initial velocity.

You can also change the above parameters with slider (x,y,vx,vy).

Equation for projectile motion with your initial conditions are displayed.

Click Initialize to reset time to zero and adjust new initial condition.

The simulation will remember the last three traces.

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**Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.**This work is licensed under a Creative Commons Attribution 2.5 Taiwan License

- Please feel free to post your ideas about how to use the simulation for better teaching and learning.
- Post questions to be asked to help students to think, to explore.
- Upload worksheets as attached files to share with more users.