If a projectile is shot at a velocity of 2 m/s2ms and an angle of pi/4π4, how far will the projectile travel before landing?

1 Answer
Jan 5, 2016

it will land about 0.638 m far.

Explanation:

We have to write down the equations of motion:

x= x_0+vcosthetatx=x0+vcosθt
y= h_0+ v sintheta t + (at^2)/2 y=h0+vsinθt+at22

where vv is the velocity of the projectile, thetaθ is the angle of the trajectory, h_0h0 the initial quota of the projectile, x_0x0 its initial position.

We have:

  • h_0=0h0=0 and x_0=0x0=0;
  • v=2 \ ms^(-1)
  • theta= pi/4
  • a=-g \ ~~ -9.81 \ ms^(-2).

We have v and thetha: we have to find t from the first equation and substitute its value in the second one.
When the projectile lands, it reaches the ground so we have y=0 at that moment.
The equations of motion at the landing are:

x= vcosthetat
0= v sintheta t - (gt^2)/2

from the first equation t=x/(vcostheta).
The other becomes:
v sin theta * x/(vcostheta) - g/2*(x/(vcostheta))^2=

Performing the calculation we eventually have:
x= sqrt( (2v^2 costheta sintheta)/g )~~ 0.638 \ m