Nuzhat at 22:37, 16 August 2010

2010-08-16T22:37:47Z

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''Helena Dedic''

A tennis ball is served at a height of 2.4 m at 30 m/s in the horizontal direction. The net is 0.9 m high at a horizontal distance of 12 m. Does the ball clear the net? If so, by how much? If not, where does it strike the net? br>

'''Solution:''' 

[[image: Proj Motion Sol 5.png|TOP]] 

Knowing that the ball travels a horizontal distance of 12 m to the net, and knowing the initial velocity, we can calculate the time it takes from eq'n 1: 

<math>\Delta x = v_{xo}t</math> 

<math>t = \Delta x/v_{xo}</math> 

t = 12 m / 30 m/s = 0.4 s

<math>\Delta y = v_{yo}t - 4.9m/s^2 t^2</math> 

<math>\Delta y = 0 - 4.9m/s^2 (0.4 s)^2</math> 

<math>\Delta y = -0.784 m</math> 

y = 2.4 m - 0.784 m = 1.616 m 

'''The tennis ball clears the net!!'''

*[[Projectile Motion|Back to Projectile Motion]] 
*[[Exercises on Projectile Motion|Back to Exercises on Projectile Motion]]

Proj Motion EX 5 - Revision history

Nuzhat at 22:37, 16 August 2010