Unit 1-1D Motion Review

Physics Review/Remediation 1D Motion

Dunham/Eckholm​

Units used in physics

​What units are used for measuring distance, time, speed, velocity, & acceleration?

​Physics Measurement	​Typical Units
​Distance/Displacement	​meters (m), kilometers (km)
​Speed/Velocity	​meters per second (m/s)
​Time	​seconds (s or sec)
​Acceleration	​meters per second per second (m/s/s or m/s2)
​Temperature	​Celsius (C)

Multiple Choice

Choose the option that is most often used to represent the measurement of distance or displacement in physics.

• Meters (m)

• Seconds (s)

• Meters per second per second (m/s/s or m/s2)

• Meters per second (m/s)

Multiple Choice

Choose the option that is most often used to represent the measurement of speed or velocity in physics.

• Meters (m)

• Seconds (s)

• Meters per second per second (m/s/s or m/s2)

• Meters per second (m/s)

Multiple Choice

Identify the correct formula to use for the following question.

How far would a car traveling at a constant speed of 15m/s drive in 30s?

• a = v_f - v_i / t

• d = 1/2at²

• v = d/t

Multiple Choice

Solve the following problem using the formula you chose in the last question.

How far would a car traveling at a constant speed of 15m/s drive in 30s?

• 2m

• 10m

• 450m

• 45m

Multiple Choice

Identify the correct formula to use for the following:

A skateboarder accelerates at 4m/s². How long will it take them to increase their speed from 2m/s to 14m/s?

• a = v_f - v_i / t

• d = 1/2at²

• v = d/t

Multiple Choice

Solve the following problem using the equation you chose in the last question.

A skateboarder accelerates at 4m/s². How long will it take them to increase their speed from 2m/s to 14m/s?

• 12s

• 4s

• 3s

• 7s

Multiple Choice

Identify which formula you would use for the following question.

How far will an object fall in 2.8 seconds? (Remember is something is falling, it is in free fall and we use the acceleration due to gravity)

• a = v_f - v_i / t

• d= 1/2at²

• v = d/t

Multiple Choice

Use the formula you chose in the last question and solve the following.

How far will an object fall in 2.8s?

• Approximately 39m

• Approximately 78m

• Approximately 20m

• Approximately 35m

​Scalar vs. Vector Quantities

​Remember that scalar quantities only require a magnitude (like speed) and vector quantities require a magnitude and direction (like vectors).

Some text here about the topic of discussion

​Review the Scalar & Vector Quantities

Subject | Subject

Multiple Select

Which of the following are vector quantities?

• 5s

• -25C

• 25m, east

• -8m/s

• 17m

This graph is a position time graph showing where an object is at each time interval. The slope of this line represents the speed, so since this is a straight diagonal line, this is object is traveling at a constant speed.

​​Position Time Graph

​This is a velocity time graph showing how fast an object is moving during each time interval. The slope of this line represents acceleration, so since this is a flat line, there is zero acceleration. This object is moving at a constant velocity.

​​Velocity Time Graph

​

​This object is moving back to home position and accelerating.

Acceleration

​

​

​This object is moving away from home position and accelerating.

Acceleration​

​

​This object is standing still.

​​No Movement

This object is moving back to home position at a constant speed

​​Constant Speed

Draw

Draw a Position Time graph showing a squirrel climbing down an 8m tree at a constant speed for 1.5s, then sitting in the tree for 2 seconds and back up the tree to the exact position it started.

This object is moving at a constant velocity in a negative direction.

Negative Direction​

​

This object is accelerating from rest in a positive direction.

​​Acceleration

This object is accelerating from rest in a negative direction.

​​Acceleration

​This object is slowing down from a high velocity.

​​Slowing Down

Draw

Draw a Velocity Time graph that shows an object speeding up from 1m/s to 5m/s in 4s, moves at a constant speed for 2s, and then slows down to 3m/s in 4s.

Multiple Select

Which of the following graphs show an object traveling at a constant velocity (not at rest or accelerating)?

Choose all that are correct.

• I

• II

• III

• IV

​Calculating Slope from a Graph

1. Find two coordinate points (x,y) and list them in a table.\

2. Use the formula to calculate slope​ m = (y₂-y₁) / (x₂ - x₁)

3. This number will give the slope of a line. It also identifies the velocity on a position-time graph and the acceleration on velocity-time graph​.

​

Subject | Subject

Some text here about the topic of discussion

Coordinate points identified and slope can be calculated. If this is a position-time graph, what does the slope tell us?

Positive Slope

​The first point to identify is (5,6) at the start of segment C.

The second point to identify is (8,3) at the end of segment C. Use the formula to calculate​ slope.

m = y₂-y₁ / x₂ - x₁

m = 3-6 / 8-5​

m = -3 / 3

m = -1 m/s​

Find Slope of segment C

​

Multiple Choice

Use these coordinate points from a position time graph to calculate slope (speed). (5,9) and (5,12)

• 0 m/s

• 3 m/s

• 10 m/s

• 12 m/s

Multiple Choice

Find the acceleration of an object on a velocity-time graph with the coordinate points: (6,4) and (10,6)

• 2 m/s²

• 2 m/s

• 0.5 m/s

• 0.5 m/s²

Free Fall

Some text here about the topic of discussion

This is the force caused by surface area. An object with greater surface area will fall slower due to air resistance. Remember crumbled ball vs. flat sheet of paper.

​Air Resistance

Absence of Air Resistance, objects will fall toward the earth at an acceleration of 9.8 m/s² or we use 10 m/s².

​Acceleration Due to Gravity

​Absence of Air Resistance (vacuum)

In conflict with our expectations, when there is no air resistance like in a vacuum or air resistance is negligible, ALL objects regardless of mass will accelerate at the same rate (10 m/s²) when in free fall.

Remember the ping pong balls vs. the golf balls or Dr. D's medicine ball vs. basketball. ​

Subject | Subject

Some text here about the topic of discussion

Multiple Choice

Which of the following is true about a 15kg bowling ball in free fall and a 25kg baby in free fall (no air resistance)?

• They will both accelerate at 10 m/s² downward.

• The baby has more mass so he/she will hit the ground first.

• They will both accelerate at 20 m/s² downward.

• They are both traveling at a constant speed.

Now, how is your displacement different from your distance? Displacement is the difference from where you ended up from where you started.

(+10-12-15​)=-17m to the left

​Displacement

Remember this is the actual distance that an object travels. You leave home and walk 10m right, then 12 meters to the left and then 15 meters more to the left. What is your distance? (10+12+15)=37m

​Distance

Distance Vs. Displacement

v = d/t (velocity equals DISPLACEMENT divided by time)

Calculate your average velocity from the previous slide when it takes you 74s?

-17m/74s = -0.23m/s or 0.23m to the left​

​Average Velocity

s = d/t (speed equals DISTANCE divided by time)​

Calculate your average speed from previous slide when it takes you 74s?

37m/74s = 0.5m/s​

Average Speed

​Average Speed vs. Average Velocity

Congratulations! You have completed the Remediation.

Now you are eligible to retake the first Unit test.

Multiple Choice

A toy car travels 5m, east in 5 seconds and then 10m west in 10 seconds. What would the toy car's average SPEED and VELOCITY?

• speed 1m/s,

  velocity 1m/s, west or +1m/s

• speed 1m/s, velocity 0.33m/s, west or -0.33m/s

• speed 0.33m/s, velocity 0.33m/s west or -0.33m/s

• speed 1m/s, velocity 0.33m/s east or +0.33m/s