Kinematics in 2 dimensions, projectile velocity help

In summary, the first question is asking how much time it will take for the angle of a javelin thrown at 34 m/s and 40° above the horizontal to decrease to 20°. The second question is evaluating the claim that Michael Jordan can jump and stay in the air for two seconds by calculating the maximum height of the jump, with Jordan's maximum jump height being estimated at one meter. The person asking for help has been struggling for 5 hours and is getting an answer of 19.6 m, but is unsure if this is correct. They are asking for assistance and expressing their frustration with the problem.
  • #1
boratphilo
2
0
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
 
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  • #2
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 that's not possible...
 
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  • #3
Welcome to the Forums,

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FAQ: Why Hasn't Anyone Answered my Question? - Moonbear said:
1) Did you show your work? Homework helpers will not assist with any questions until you've shown your own effort on the problem. Remember, we help with homework, we don't do your homework. We already passed those classes; it's your turn to do so.
 

FAQ: Kinematics in 2 dimensions, projectile velocity help

1. What is kinematics in 2 dimensions?

Kinematics in 2 dimensions is a branch of physics that deals with the motion of objects in two-dimensional space. It involves studying the position, velocity, and acceleration of an object as it moves in two perpendicular directions.

2. How is projectile motion different from regular motion?

Projectile motion is the motion of an object that is launched or thrown into the air and moves in a curved path due to the influence of gravity. Unlike regular motion, which follows a straight path, projectile motion involves both horizontal and vertical components of motion.

3. What is the formula for calculating projectile velocity?

The formula for calculating projectile velocity is V = √(V0x2 + V0y2), where V0x is the initial velocity in the horizontal direction and V0y is the initial velocity in the vertical direction.

4. How does air resistance affect projectile motion?

Air resistance, also known as drag, can affect the speed and trajectory of a projectile. It acts in the opposite direction of the projectile's motion and can cause it to slow down and deviate from its expected path.

5. What factors can influence the range of a projectile?

The range of a projectile is influenced by its initial velocity, angle of launch, and the effects of air resistance. Other factors such as the mass and shape of the object can also impact the range of a projectile.

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