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PHYS 11 - Kinematics
Fichas del conjunto (52)
- 11. What is the "100-Mile Diet"? What is the idea behind it and the advantages (and challenges) of it?A term used to describe a diet that consists only of food grown within a 100 mile radius of the consumer's table. A term used for people following this diet is "locavores", since they only eat locally grown food.
The idea is to reduce the distance that food has to travel from the farm to the table. These "food miles" directly affect that environment, as they result in carbon emissions from the trucks, planes, and ships used for transporting this food, and also from the energy used to run the refrigeration units required for transporting and storing the food.
Can be challenging for many parts in Canada, especially during winter.
However, the idea has a lot of benefits e.g. consumers will become more aware of the food that is available in your own region and the seasons in which it is available. This will bring business to local farmers, selling food at farmers' markets or directly from their farms. The food will be fresher, of a higher quality, and less likely to be processed and packaged. - 22. Draw a distance-time graph of uniform motion
- 33. Draw a speed-time graph of speed not changing over time
- 44. What type of motion do these examples represent? a) Prasad running around the track at a steady pace b) Rosa dives into the pool and swims to the opposite wall c) The postal worker walks along the sidewalk and up driveways, deliving the mail d) The Go bus from Orangeville travels along Hwy 10, stopping at Caledon and Victoria before stopping at the bus terminal in Bramptonnon-uniform motion
- 55. What can you learn from this speed-time graph?The speed changes every second. This is not uniform motion.
- 66. What can you learn from the following data for a ball in motion rolling down a ramp? Time (s) Distance (m) 0 0 0.2 0.14 0.4 0.58 0.6 1.30 0.8 2.30The distance changes by different amounts for each 0.2s interval
- 77. Classify either uniform or non-uniformNon-uniform
- 88. What is speed and what relationship does it describe? On a distance-time graph, what is this relationship equivalent? What information does speed not provide?Speed is the rate of motion and describes a ratio of distance to time.
Looking at a distance-time graph, the ratio of distance to time is equivalent to calculating the slope of a line.
The direction - 99. How do you calculate the slope (using rise over a run)? what about for a distance-time graph?slope = Δy/Δx
OR
slope = y2-y1/x2-x1
For distance-time graph:
slope = d2-d1/t2-t1 or v = d2-d1/t2-t1
Where v is the symbol for speed - 1010. What is an equation for the ratio v = d2-d1/t2-t1?speed = change in distance / change in time
or
v=Δd/Δt - 1111. What is the speed of a train that can travel 255 km in 3.0 hours?v = Δd/Δt
v = 255 km/3.0 h
v = 85 km/h - 1212. At Pearson international Airport, how long does it take (in minutes) to ride the part of the moving sidewalk in Pier F that has a constant speed of 7.2 km/h? This portion of the moving sidewalk is 212 m in length.v = Δd/Δt
Δt = Δd/v
212 m x 1 km/1000m = 0.212 km
Δt = 0.212 km/7.2 km/h
= 0.0294 h
convert to minutes
0.0294 h x 60 minutes / 1 hr = 1.764 min
Δt = 1.8 min - 1313. What is a position value?When you assign a direction to a distance
- 1414. What are scalar quantities? What is a vector quantity?Measurements or calculated value with units.
The same thing as scalar quantities but they also include direction. - 1515. What is the symbol for position?{d}
(vector quantity) - 1616. What is displacement and what does it mean?Δ{d}
It means the most direct path between two points - 1717. How do you calculate the total displacement?Just look at the start and finish
e.g. = 0 since Tara started and finished at bus stop - 1818. what do you need to consider when calculating total distance?You need to consider just the measurements, without the directions
- 1919. For position versus time graphs, what can you instantly recognize relating to uniform motion?A constant slope - uniform motion
- 2020. What does it mean for a position vs time graph relating to direction and speed?If lines extend in different directions, this corresponds to the object/person travelling in different directions.
The steeper the line, the faster the motion - 2121. For a position versus time graph, what can indicate a change in the velocity and direction?By the changes in the slope
- 2222. James drives his car 12 km [N] in 8.8 minutes, stops for gas (6.2 min), continues north for another 35 km in 22.1 minutes, stops to buy apples for 10.3 minutes, and then drivers 26 km [S] in 17. 5 minutes. 1) Create a data table of this data 2) What was the total distance that James travelled? 3) What was Jame's displacement at 37.1 min? 4) What was Jame's total displacement?time (min) Position (km) [N]
0 0
8.8 12
15.0 12
37.1 47
47.4 47
64.9 21
2) 12 + 35 + 26 = 73 km
3) 47 m [N]
4) 21 m [N] - 2323. What does a position-time graph represent? What does the slope represent? Mathematically represent this vectorvelocity
A ratio of change in position to change in time.
slope = (vector)d2-(vector)d1/t2-t1
Thus ratio is called velocity
{v} = {d2}-{d1}/t2-t1
velocity = change in position/ change in time
OR
{v]=Δ{d}/Δt - 2424. Using a graph, how do you calculate speed or velocity for non-uniform motion?Take the slope of a line that connects the endpoints of the time frame of interest.
- 2525. What is the difference between average speed and average velocity? How do you calculate average speed and average velocity?Average speed is scalar quantity, average velocity is a vector quantity, including direction.
Average speed = total distance/total time
The symbol for average speed is v(av)
Average velocity = total displacement/total time
The symbol for average velocity is {v}av - 2626. What's different about position-time graphs containing smooth curves instead of straight lines?They don't' have constant slopes, meaning they don't represent constant velocity (i.e. constant slopes for position-time graphs indicate constant velocity)
Since the slopes are not constant, these graphs do not represent uniform motion. There are changes in the slopes, meaning that there are changes in velocity, so these graphs represent non-uniform motion
- 2727. How do you find the average velocity for a position versus time graph with a smooth curve?By drawing a straight line to connect any two points on the curve
- 2828. How do you get a very good approximation of the slope of a curve? What is the name of a technique that uses this idea?By drawing a straight line between the endpoints there are very close
Drawing a tangent to the curve. - 2929. What does the dotted line represent?represents the slope of the curve (tangent line) at the midpoint between the two points shown on the curve.
- 3030. What are you finding when you calculate the slope of tangents?The instantaneous velocity (velocity of object at the exact time where the tangent touches the curve)
- 3131. What does a line on a velocity-time graph represent?slope = {v2}-{v1}/t2-t1
slope = change in velocity/change in time
This quantity is called acceleration and indicates at what rate the velocity of the object is changing.
acceleration = change in velocity/change in time
{a} = {v2}-{v1}/t2-t1
{a} = Δ{v}/Δt
since Δ{v} is in units m/s
and Δt is in units /s
{a} is in units m/s^2 - 3232. Using position-time graphs, velocity-time graphs and acceleration-time graphs, represent a stationary object, constant motion and motion with a constant acceleration
- 3333. Consider a position versus time graph of a slope start at some point in a positive direction away from the origin. The object then starts to move towards the origin, which can be considered negative direction. What direction is acceleration occuring?The slope of the velocity-time graph is positive. This means the acceleration is happening in the opposite direction to the actual motion of the object in the position-time graph.
The velocity value indicates that the object is slowing down (decelerating) and that is what is indicated by an acceleration value that has the opposite direction the object's motion. - 3434. Explain this graph in terms of velocity, and acceleration and explain what the velocity-time graph would look likeThe object moves away from the origin very quickly and then slows down. The acceleration is negative, meaning it moves in the opposite direction to the motion of the object. This is indicated by the object slowing down. (Velocity values started as large positive values and decreased to small positive values.)
- 3535. Describe the motion of the slope in relation to velocity and accelerationThe object starts its motion at a point that is in a positive direction away from the origin and moves back towards the origin. The slopes of the position-time graph start with small negative numbers and ends with larger negative numbers. This indicates that the object is moving towards the origin (in the negative direction) and that it is increase in speed. The acceleration is also negative, but this corresponds directly to the direction in which the object is travelling, so the object is actually accelerating back towards the origin.
- 3636. Does the 100-Mile Diet completely eliminate all environmental concerns?No. Farmers and store owners need to carefully consider how produce travels from farm to store. These distances are called "food miles"
- 3737. Are all "food miles" the same?No, some routes involve lots of stopping and starting, speeding up and slowing down. Also the choice between transport e.g. trucks running on diesel fuel or smaller tonnage trucks running on gasoline.
It is apparent that all food miles do not have the same environmental effect. The key is to try to minimize the impact of any food miles on the environment. - 3838. When considering how produce travels, you could either look at the total distance it travels on ground (the route it takes) or the displacement (how far away it ends up from where it started). What is the most meaningful quantity?Distance as it takes changes in direction into account.
- 3939. What is constant velocity and what is its formula? What is the formula also used for?constant speed and direction
{v} = Δ{d}/t
The same formula is used to find the slope of a line on a position-time graph. - 4040. what is average velocity and what is its formula?Object has change its speed and/or direction
{v(av)} = total displacement/total time
Not always important since can involve reversed directions - 4141. How do you find the corresponding velocity-time graph using a distance-time graph? What can you further do?By calculating the slope at each point on the distance-time graph.
You can also find the acceleration-time graph by calculating the slope at each point on the velocity-time graph - 4242. How do you calculate the displacement for a velocity time graph?By finding the area e.g. A = l*w for constant velocity
- 4343. How do you create a position-time graph from a constant velocity time graph? (2 methods) e.g. car travelling at 80 km/h [east] for 2.0 hours (find the displacement)displacement = Δ{d} = {v}Δt
= 160 km [east]
Method 1: find displacement every 0.25 h
e.g.
time (h) = 0 at position (km) [east] = 0
time (h) = 0.25 at position (km) [east] = 20
...
Method 2: You only need to know the total displacement to create position time graph (since constant velocity-time graph can be derived from a position-time graph that exhibits a straight line) - 4444. How do you find the displacement for a velocity time graph of changing velocity when {v1} = 0? Is this useful?Using the area of a triangle
A = 1/2 b h
base = Δt, height = {v2}
Not very useful, only works for {v1} = 0 - 4545. how do you find the displacement for a constant slope (constant acceleration) regardless of the values of {v1}?Δ{d} = 1/2 *({v1}+{v2})Δt
- 4646. What is the area of a trapezoid?Δ{d] = 1/2 ({v1}+{v2})Δt
- 4747. What determines the trajectory of a ball?Acceleration due to the force of gravity determines the shape of the flight path of a ball
- 4848. What kind of paths does throwing a ball and jumping follow?parabolic curves
- 4949. Explain the path of a ball rolling off a shelf with no initial downward velocity, but with a small horizontal velocity breaking down its velocity vectors into vertical and horizontal components and elaborate on this.It has both vertical and horizontal displacement, as its velocity changes in size and direction.
The horizontal vectors are the same size throughout: constant horizontal velocity, no acceleration in the horizontal direction.
The vertical velocity gets progressively bigger, changing vertical velocity because of acceleration due to gravity. - 5050. Explain what happens to the path of projection when you change the intial velocity and angle of projection (e.g. firing an arrow)As the launch angle is increased, the horizon displacement increases until a launch angle of 45 degrees is reached. At angles higher than 45, the horizontal displacement decreases but the maximum vertical height increases.
As the initial velocity increasesTg, both the vertical height and the horizontal displacement increases, and the projectile has a longer flight time. - 5151. a) Does this graph represent uniform or non-uniform motion? Justify b) Describe the motion of this shipment of potatoes c) Calculate the velocity of the train that carried the potatoes for the first three hours d) What was the trains acceleration during this same time frame? e) total distance travelled by train f) If average fuel consumption for trains is 1.2L/100 Km, then find the fuel consumption of the train carrying the potatoes g) What was the total distance that the potatoes travelled by truck? h) If average fuel consumption for trucks is 30L/100 Km, then find the fuel consumption of the truck carrying the potatoes
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- Fichas sobre PHYS 11 - Kinematics, creado por Alex Obray el 16/12/2015.
- Creado por
- Alex Obray · dic 2015
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- 3 jun 2016
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