Posted by **Kristina** on Thursday, December 18, 2008 at 9:06pm.

This is a projectile motion problem where I need to find the velocity and angle I launch a ball at to hit a ship. The ball is on a cliff 400 m high, and the ship is 250 m away from the cliff. The ship is moving away at a velocity of 40 m/s. What velocity and angle should I launch the ball at so it hits the ship? And how do i solve this? Thank you.

- Physics -
**bobpursley**, Thursday, December 18, 2008 at 9:21pm
The ship is moving at 40m/second? I dont believe it. That is over 80miles/hour.

You have to aim at where the ship will be.

let it be 250+x

but x=40*timeinair

now time in air is found from....

1) hf=hi+ViSinTheta*time-1/2 g time^2

Notice that is a quadratic.

and the horizontal equation..

250+x=Vicostheta*time

2)250+40*time=ViCostheta*time

So you have two equations, two unknowns. Which means you can choose an arbritary value for one. Theta is the most complicated, so choose a launch angle. Lets make Theta 32 deg.

Find the cos32, sin32 and put those in the equation.

Now in the second equation, solve for Vi in terms of time. Now put that value of Vi in the first equation, and solve for time. You have it all.

## Answer This Question

## Related Questions

- Calc - A ball is launched straight up from the edge of a cliff that is 250 m ...
- Physics - A batted baseball is hit with a velocity of 47.3 m/s, starting from an...
- College Physics - A batted baseball is hit with a velocity of 47.3 m/s, starting...
- College Physics - A batted baseball is hit with a velocity of 47.3 m/s, starting...
- Physics - A man is standing on a cliff and throws a ball outward 50m/s at an ...
- Physics(science) - A ball's projected at an angle X to the horizontal from a ...
- Physics Projectile Motion - A ball is kicked with an initial velocity of 21 m/s ...
- math - A ball is thrown from the edge of a cliff with an initial velocity of 60·...
- Physics projectile motion - A football player kicks a ball with a soeed of 22.4 ...
- Physics - A batter hits a pitched ball when the center of the ball is 1.35 m ...

More Related Questions