# Homework Help: Kinematics in 2 dimensions, projectile velocity help

1. Sep 18, 2006

### boratphilo

Question 1-
In the javelin throw at a track-and-field event, the javelin is launched at a speed of 34 m/s at an angle of 40° above the horizontal. As the javelin travels upward, its velocity points above the horizontal at an angle that decreases as time passes. How much time is required for the angle to be reduced from 40° at launch to 20°?

Question 2-
Michael Jordan, formerly of the Chicago Bulls basketball team, has some fanatic fans. They claim that he is able to jump and remain in the air for two full seconds from launch to landing. Evaluate this claim by calculating the maximum height that such a jump would attain. For comparison, Jordan's maximum jump height has been estimated at about one meter.

IF ANYONE KNOWS HOW TO DO THIS...........HELP WOULD BE GREATLY APPRETIATED
thanx

2. Sep 18, 2006

### boratphilo

i've been stuck on these problems for 5 hours now.......and i need help

The second one is so tough........i mean i took into account the 2 seconds.......and i'm getting 19.6 m as the answer.......but thats not possible.....

Last edited: Sep 18, 2006
3. Sep 19, 2006

### Hootenanny

Staff Emeritus
Welcome to the Forums,

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