Projectile motion of a kicked ball

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SUMMARY

The discussion focuses on calculating the time a ball is in the air after being kicked with an initial velocity of 15 m/s at an angle of 37 degrees from a height of 0.8 m. The initial attempt to calculate the time of flight incorrectly assumed the ball was kicked from ground level. The correct approach involves using the formula -y = v_yt - (1/2)gt² to account for the initial height. The final solution requires solving a quadratic equation to determine the total time until the ball reaches the ground.

PREREQUISITES
  • Understanding of projectile motion principles
  • Familiarity with kinematic equations
  • Knowledge of vector resolution
  • Basic algebra for solving quadratic equations
NEXT STEPS
  • Study the derivation and application of the kinematic equation -y = v_yt - (1/2)gt²
  • Learn how to resolve vectors into their components in projectile motion
  • Practice solving quadratic equations in the context of physics problems
  • Explore the effects of initial height on projectile motion calculations
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Students studying physics, particularly those focusing on mechanics and projectile motion, as well as educators seeking to clarify concepts related to time of flight in projectile scenarios.

fiziks09
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Homework Statement


A ball is kicked in the air with an initial velocity of 15m/s at an angle of 37 degrees; 0.8 m above the ground. How long is the ball in the air?


Homework Equations





The Attempt at a Solution


I resolved the vector into its components and the y component was 9.02
I calculated time to reach maximun height using t = 9.02/9.8 = 0.92

and then the whole time of flight was = 2*0.92 = 1.8s.

please is this correct?? did i do the right thing here?? thanks
 
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It is not correct. The ball is kicked from 0.8 m above the ground. And it is required to find the time to reach the ground.

Use the formula

-y = v_yt - <br /> \frac{1}{2}gt^2

Solve the quadratic to find t.
 
Last edited:
fiziks09 said:
I resolved the vector into its components and the y component was 9.02
I calculated time to reach maximun height using t = 9.02/9.8 = 0.92

and then the whole time of flight was = 2*0.92 = 1.8s.

please is this correct?? did i do the right thing here?? thanks

Don't forget that the ball was kicked from 0.8m above the ground...
 

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