The Vector Factor
A projectile is shot upward in a parabolic trajectory. On the way up the vertical velocity is ________ & ________.
positive & decreasing
What is the range of a projectile?
horizontal displacement
A student walks 30 feet east and then walks 40 feet north. What is the magnitude and the approximate direction of his displacement?
50 feet NE
A New Orleans Saints punter kicks a football on the field with an initial horizontal velocity of 6 m/s and an initial vertical velocity of 25 m/s. How long does it take for the football to reach the highest point on its flight?
2.55 seconds
A flower pot is blown horizontally off the top of an office building at 5 m/s. The office building is 80 meters tall. What is the initial vertical velocity of the flower pot?
0 m/s
A projectile is shot upward in a parabolic trajectory. On the way up, the horizontal velocity is ________ & ________.
constant & positive
How does air resistance affect the range and maximum height of a projectile?
Air resistance reduces the range and maximum height of the projectile.
A small airplane is flying south at 45 m/s with a cross wind of 10 m/s from the east. What is the magnitude and approximate direction of the airplane relative to a man standing on the earth below?
46.1 m/s SE
A New Orleans Saints punter kicks a football on the field with an initial horizontal velocity of 6 m/s and an initial vertical velocity of 25 m/s. How long is the football in flight?
5.1 seconds
A flower pot is blown horizontally off the top of an office building at 5 m/s. The office building is 80 meters tall. How long does it take for the flowerpot to reach the ground?
4 seconds
A projectile is shot upward in a parabolic trajectory. At the top, the horizontal velocity is ________ & ________ and the vertical velocity is ________.
constant & positive; zero
A cannonball is shot from the battlefield to the nearby castle. Draw the position, velocity, and acceleration graphs for the vertical motion of the cannonball
Position - Curve - parabola starting from and ending at 0 with max displacement at mid-point.
Velocity - Diagonal - upward positive, decreasing velocity; 0 at mid-point; downward negative, increasing velocity
Acceleration - Horizontal - constant & negative -9.8 m/s2
The captain walks south at a velocity of 1 m/s on a large cruise ship that is traveling due west at 4 m/s. What is the resultant velocity and approximate direction of the captain's walk relative to a nearby island?
4.12 m/s SW
A New Orleans Saints punter kicks a football on the field with an initial horizontal velocity of 6 m/s and an initial vertical velocity of 25 m/s. How far did the football travel prior to hitting the field?
30.6 m forward
A flower pot is blown horizontally off the top of an office building at 5 m/s. The office building is 80 meters tall. How far away from the building does the flower pot hit the sidewalk?
20 meters
An object has a positive velocity and a negative acceleration, it is ________.
slowing down
A cannonball is shot from the battlefield to the nearby castle. Draw the position, velocity, and acceleration graphs for the horizontal motion of the cannonball
Position - Diagonal -starting from 0 and ending with max displacement at end.
Velocity - Horizontal - constant & positive
Acceleration - Zero
A river ferry is crossing a river. If the ferry is headed due east with a speed of 5.2 m/s relative to the water and the river's velocity is 3.0 m/s to the north, what will the magnitude of the boat's velocity be relative to the earth?
6 m/s NE
A New Orleans Saints punter kicks a football on the field with an initial horizontal velocity of 6 m/s and an initial vertical velocity of 25 m/s. What was the final vertical velocity of the football the instant before it hit the ground?
-25 m/s
A flower pot is blown horizontally off the top of an office building at 5 m/s. The office building is 80 meters tall. What is the final vertical velocity of the flower pot?
-39.2 m/s
An object has a negative velocity and a negative acceleration, it is ________.
speeding up
A cannonball is launched toward a distant castle. If the mass of the cannonball is increased while the angle of launch of the cannonball is held constant; how must the initial velocity of the cannonball be changed to maintain a constant range and still hit the castle? (The knight's neglect air resistance.)
No change in initial velocity.
A canoe is paddling downstream at a velocity of 4 m/s relative to the water. The current is moving at 2 m/s. What is the resultant velocity of the canoe to an observer on the river bank?
6 m/s downstream
A New Orleans Saints punter kicks a football on the field with an initial horizontal velocity of 6 m/s and an initial vertical velocity of 25 m/s. What was the height of the football at the top of its flight?
31.89 m upward
A flower pot is blown horizontally off the top of an office building at 5 m/s. The office building is 80 meters tall. What is the final horizontal velocity of the flower pot?
5 m/s