A projectile is shot at an angle of pi/8 and a velocity of 27 m/s. How far away will the projectile land?

1 Answer
May 18, 2017

52.59m

Explanation:

![https://www.ilephysique.net/physique_terminalehttp://-mouvement-projectile-champ-pesanteur.php](https://useruploads.socratic.org/Qg9760t4RO5PXRQNFm0G_physique_terminale-mouvement-projectile-champ-pesanteur_01.gif)

We have to calculate the initial speed in x and in y:
V_(0x)=V_ocos(theta)=(27)cos(pi/8)~~24.94m/s
V_(0y)=V_osin(theta)=(27)sin(pi/8)~~10.33m/s

We have to know when the projectile will land.
We are going to calculate when the projectile is at its maximum height and multiply it by 2. Let's use the equation of the speed (velocity) for an object with acceleration:
V_y=V_(0y)+aDeltat

The acceleration is -9.8m/s^2 because of earth's gravity. The speed in y at its highest hight is 0:
0=10.33+(-9.8)Deltat => Deltat~~1.054s

And to find the time it took the projectile to land we multiply this answer by 2:
1.054*2~~2.1s

To find the distance in x we have to use the equation of distance:
x=x_(0)+v_(0x)t+1/2 at^2
Theres no acceleration and x_o=0.
=> x= (24.94)(2.1)
=> x~~52.59m


We could have used a formula to calculate it directly:
R=(u^2Sin2theta)/g

This method is explained in this answer:
https://socratic.org/questions/a-projectile-is-shot-at-an-angle-of-pi-8-and-a-velocity-of-65-m-s-how-far-away-w?source=search