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Projectile motion?

  • #1

Homework Statement



Hi, i have a small problem, can you guys help?
1.
A man jumps a maximum horizontal distance of 3 meters. How far can he jump on the moon, where downward acceleration is g/6?

#2
A 2 meter tall basketball player, 10 meters away from the hoop 3.05 meters high, launches a basketball at a 45 degree angle. What initial velocity must he use to get it in the hoop without touching the rim?


Homework Equations



Vx= vintial*(cos theta)
X-displacement= Vx*T
V-y final= V-initial (sin theta) + AT
X displacement= V * T


The Attempt at a Solution


For number one-
I split it in half- so now I'm trying to solve
A ball is rolled off the edge of a table and lands 1.5 meters away at 45 degrees. What is Vx,
Vy final, T, and height of the table?

So first, I use
Height= 1/2 g t^2
H= 4.9 *t^2

Since D= Vx * T,
Then T= D/vx
So H= 4.9 * D^2/vx^2
Tan 45= Vy/Vx,
Vx= Vy/tan45
D= 1.5 meters
So H= 4.9 * 2.25/ (vy/tan45)
tan45=1
H= 4.9* 2.25/vy^2

and this is where i stop.

For the second question, I was thinking of perhaps the changing it to

A ball is thrown from ground level, at a 45 degree angle, to a hoop 1.05 degrees.
After that, I have no clue

Thanks for answers!

Homework Statement





Homework Equations





The Attempt at a Solution


Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
1,137
0
your answer and question for 1st dont match. please check.
 
  • #3
1,137
0
well started for ques2

now you can understand that the ball must the hoop during second half of its flight.
and also that it will not complete its flight.

so think of it as when the ball reaches point 1.5 along y axis, its x distance should be 10
 
  • #4
your answer and question for 1st dont match. please check.
well, no I was just looking at it from a different perspective. Instead of a man jumping 3 feet at 45 degrees, I start from his highest point and act as if he is a ball rolling off a table and landing 1.5 meters away at 45 degrees.
 
  • #5
1,137
0
Good that you know that range is max at 45o.

now using full flight of half flight as you did, you donot need to calculate the max height or final velocities. because they will change when jumping on moon.

Can you tell me what will remain same while jumping on earth or moon???
 

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