# Calculating the tangential component of the force acting on a projectile

1. Jul 10, 2008

### kylera

1. The problem statement, all variables and given/known data
Consider a projectile launched horizontally out the window of a tall building at a speed v(0). Determine an expression for the tangential component of the force acting on the projectile in terms of m, g, t, and v(0). Assume that the air has a negligible effect on the motion.

2. Relevant equations
F = ma, mostly deductions.

3. The attempt at a solution
V(h) = the horizontal velocity = v(0)
V(v) = the vertical velocity = mt

From here, I assume that since the horizontal velocity does not change because of negligible air resistance, F(h) = horizontal element of the total force applied on the projectile = zero. F(v) = mass * gravity = mg. However, this brings me to where I'm stuck -- I can't figure out how to determine the angle at which the projectile is falling. It can't be straight down. Do I find the angle using the velocities instead and then apply it to the force?

2. Jul 10, 2008

### tiny-tim

Hi kylera!

Yes, the angle changes with t …

so find the horizontal and vertical components of the velocity as a function of t.

3. Jul 10, 2008

### kylera

Done! Thanks!