Module 1 Review
What is the main difference between a scalar quantity and a vector quantity?
A vector quantity has information about direction, while a scalar quantity does not.
What two conditions must be met before you can use the three equations derived in this module?
1) Motion must always occur in a straight line
2) Acceleration of the object must be constant
Mason, standing on the edge of a 30 foot cliff, throws a ball straight up into the air. The ball travels 50 feet up and then falls to the bottom of the cliff. What would be the total distance traveled? What would be the displacement of the ball?
Distance: 130 feet
Displacement: -30 feet
Brayden is bored, so he drops a rock from a 55 m cliff. How long does it take to hit the ground?
Time: 3.4 seconds
For some reason, somebody let Aidan fly an airplane. His plane's velocity has an x-component of -155 mph and a y-component of -45 mph. What are the magnitude and direction of the plane's velocity?
Magnitude: 161 mph
Direction: 196°
Which is a vector quantity: speed or velocity?
Velocity
What is the definition of free fall?
The motion of an object when it is falling solely under the influence of gravity?
Aidan has eaten too much food and is now so stuffed he can hardly move. It takes him 3.5 minutes to crawl the 22 meters from the couch to the refrigerator and 11 meters back towards the couch (before he gives up and just lies on the floor). What is Aidan's average speed and average velocity?
Average speed: 9.4 m/min
Average velocity: 3.1 m/min
Denver is flying an airplane and really really wants to land. He accelerates at -3.1 m/sec^2 down a 3.8 km runway. What is the fastest speed with which he could land in order to assume that the airplane will stop before reaching the end of the runway (and perhaps blowing up)?
Fastest velocity: 150 m/sec
Brayden the Dodo Bird flies 258 meters due east (θ = 0°) and then flies 189 meters in a NW direction (θ =135°). What is Brayden the Dodo Bird's final displacement?
Displacement: 183 m at 47.2°
What physical quantity is represented by the slope of a position-versus-time graph?
Velocity
Jack is a very picky physicist, and he says that no object can really experience free fall when falling near the surface of the earth. Explain why Jack is technically correct.
All falling objects experience air resistance, which means they are not falling solely under the influence of gravity.
Time: 100 seconds
A train slows as it approaches a curve…a good thing, too, because Jack's physics students had tied him to the tracks after he assigned them too much homework.
What is the acceleration of the train if its velocity was 62 mph and the brakes are applied for 12 seconds over a displacement of 800 feet?
Acceleration: -4 ft/sec^2
Denver is trying to swim across the English channel to get to the fish and chips on the other side. He swims with a velocity of 3.2 km/hr at 290°. If the current is moving against him at 0.89 km/hr at 32°, what will be his actual velocity vector?
Vector: 3.1 km/hr at 307°
Brayden is reading through Denver's lab notebook (the cheater…) and he notices a number written down: 12.3 m/sec^2. What is the physical quantity that Denver measured?
Acceleration
On the moon, gravity is significantly weaker than on earth. Would you expect the acceleration due to gravity on the moon to be larger, smaller, or the same as compared to the acceleration due to gravity on earth?
The acceleration due to gravity on the moon is smaller than that on earth.
Denver slows his Lamborghini from 72 mph to 65 mph in 1.8 seconds. What is his acceleration in miles/sec^2?
Acceleration: -0.001 miles/sec^2
A cheetah, mistaking Mason for a gazelle and thinking he might have a tasty lunch, accelerates in a straight line from a velocity of 10 m/sec to 15.2 m/sec in 2.1 seconds. How much distance was covered during this acceleration?
Distance: 26 meters
Jack just got a new MasterCraft and is hyped to take it out for a spin. He travels southwest (θ = 205°) at 15 knots against a 4-knot current that is flowing north (θ = 90°). What is the boat's actual velocity?
(Note: the unit "knots" means "nautical miles per hour." Thus, it is a velocity unit.)
Velocity: 14 knots at 189.3°
Aidan's velocity is 0. Does that mean that his acceleration is 0? Why or why not?
His acceleration does not have to be 0 because it merely measures the change in velocity.
Denver throws a cantaloupe up in the air with an initial velocity of 1.2 m/sec. If the cantaloupe is caught at exactly the same height from which it was thrown, what will its velocity be?
Velocity: -1.2 m/sec
Jack needs to go buy some Dr. Pepper (badly), so he hops in his Corolla. His initial velocity on the way to the store is 62 m/sec, and he accelerates at -5.0 m/sec^2 for 9.2 seconds. What is his final velocity?
Final velocity: 16 m/sec
Upon discovering a hole in the ground, Aidan decides to jump in and see how long it will take for him to hit the bottom. Neglecting air resistance and the time for sound to travel, how deep is the hole if it takes 5.3 seconds for Aidan to hit the bottom?
Distance: 140 m
Mason finds a buried treasure map! It says to walk 525 meters due west (θ = 180°) then turn to a heading of 50° and walk for 375 m. If he follows the instructions, what is his final displacement?
Displacement: 404 m at 134.7°