How Long Something Stays in Air Calculation. Help Needed

  • Thread starter Thread starter student54321
  • Start date Start date
  • Tags Tags
    Air Calculation
Click For Summary
SUMMARY

The discussion focuses on calculating the time a kangaroo remains in the air after jumping to a height of 3.0 meters. The relevant equation used is d = vf(t) - 1/2 a (t)², where d is the height, a is the acceleration due to gravity (9.81 m/s²), and vf is the final velocity at the peak (0 m/s). The initial calculation yielded a time of 0.78 seconds, which was incorrect for the total airtime. The correct approach involves recognizing that the time to ascend is equal to the time to descend, thus the total airtime is double the ascent time, resulting in a final answer of 1.56 seconds.

PREREQUISITES
  • Understanding of kinematic equations
  • Basic knowledge of gravity (9.81 m/s²)
  • Ability to solve quadratic equations
  • Familiarity with the concept of projectile motion
NEXT STEPS
  • Review kinematic equations in physics
  • Study projectile motion and its properties
  • Practice solving problems involving maximum height and time of flight
  • Explore the concept of symmetry in projectile motion
USEFUL FOR

Students studying physics, educators teaching kinematics, and anyone interested in understanding projectile motion calculations.

student54321
Messages
11
Reaction score
0

Homework Statement


Jumping straight up, how long will a kangaroo remain in the air if it jumps through a height of 3.0m?


Homework Equations


d=vf(t) - 1/2 a (t)2

I Think?


The Attempt at a Solution


Defined all variable
d=3.0 m
a=9.81 m/ss
vf=0m/s2

then:
d=vf(t) - 1/2 a (t)2
3.0=0 - 4.905(t)2
0.61=(t)2
t=Square root of 0.611
t=0.78

I got the wrong answer. But when I multiplied my answer by two I got the right answer. Don't know why so I'll need some help here.

And I know I skipped some calulation steps in my answer, I have them written on paper.
 
Physics news on Phys.org
Just thought about it. Is it because what goes up must come down? So it needs to be 2 times the time, I just calculated for the time to the top of the parabola. Am I right?
 

Similar threads

Need help with this question regarding kinematics.
  • · Replies 6 ·
Replies
6
Views
2K
Solving for Time to Reach Ground: Calculating Velocity of Sound over 50m
  • · Replies 2 ·
Replies
2
Views
2K
How do I calculate work in two-dimensions and find the final velocity and time?
  • · Replies 8 ·
Replies
8
Views
2K
How Long Does It Take a Sled to Reach 24 m/s on an Incline?
  • · Replies 6 ·
Replies
6
Views
2K
Determine when (m), and how long the rocket should fire.
  • · Replies 2 ·
Replies
2
Views
2K
Another Kinematics Problem (I have solution)
  • · Replies 7 ·
Replies
7
Views
3K
How Do You Calculate the Meeting Point of Two Stones Thrown from a Cliff?
  • · Replies 1 ·
Replies
1
Views
2K
How Do You Calculate the Final Velocity of a Projectile?
  • · Replies 1 ·
Replies
1
Views
2K
Kinematics question, easier way to do this?
  • · Replies 6 ·
Replies
6
Views
3K
Baseball in the air 2D motion question
  • · Replies 1 ·
Replies
1
Views
2K