# projectile motion

## another example of projectile motion

You can probably think of other examples of projectile motion. One is shown in the Figure 1.3. The cannon shoots a ball straight ahead, giving it horizontal motion. At the same time, gravity pulls the ball down toward the ground. Q: How would you show the force of gravity on the cannon ball in the Figure 1.3? A: You would add a line pointing straight down from the cannon to the ground.

## combining forces

When the archer releases the bowstring, the arrow will be flung forward toward the top of the target where shes aiming. But another force will also act on the arrow in a different direction. The other force is gravity, and it will pull the arrow down toward Earth. The two forces combined will cause the arrow to move in the curved path shown in the Figure 1.1. This type of motion is called projectile motion. It occurs whenever an object curves down toward the ground because it has both a horizontal force and the downward force of gravity acting on it. Because of projectile motion, to hit the bulls eye of a target with an arrow, you actually have to aim for a spot above the bulls eye. You can see in theFigure 1.2 what happens if you aim at the bulls eye instead of above it.

## instructional diagrams

No diagram descriptions associated with this lesson

## questions

to hit the bulls eye of a target, you have to aim an arrow

``````a) at the center of the bulls eye.

-->  b) above the bulls eye.

c) below the bulls eye.

d) to one side of the bulls eye.
``````

examples of objects that have projectile motion include

``````a) moons of planets.

b) artificial satellites.

-->  c) paintballs.

d) all of the above
``````

when an arrow is shot from a bow, forces acting on the arrow include the

``````a) elastic force of the bow.

b) force of gravity.

c) force of friction.

-->  d) all of the above
``````

a cannonball shot from a cannon has projectile motion.

``````-->  a. true

b. false
``````

an object with projectile motion constantly changes direction.

``````-->  a. true

b. false
``````

## diagram questions

No diagram questions associated with this lesson