Download Motion, Speed, and Force (PS. 10)

Motion, Speed, and Force (PS. 10)
I.
Measuring Motion
A. _____________________________ – how far an object has moved
1. Common unitsà ___________________________
2. Formula à ______________________________
3. _______________________________à distance direction; Ex. 25 km, North
*** Distance or Displacement?
a. 45 m à __________________
b. 2 cm, left à_______________
c. 60 km, West à _____________
d. 100 cm à _______________
B. ________________________- how far an object travels in a certain amount of time
1. Common unitsà ___________________________________
2. Formula à ________________________________________
3. ____________________ à speed and direction; Ex. 55 km/h, East
*** Speed or Velocity?
a. 20 m/s à__________________
c. 5 m/s à__________________
b. 70 km/h, West à_____________
d. 9.8 m/s, down à________________
C. _______________________- refers to how long an object takes to travel a distance
1. Common unitsà _______________________________________
2. Formula à ___________________________________________
Practice Problems
1. A car travels 1000 meters in 20 seconds. What is its speed?
2. An airplane travels at 240km/hr for 2 hours. What distance is traveled?
3. A taxicab travels 140 km at a rate of 70 km/hr. How long does the trip take?
D. __________________________________- change in velocity
1. Common unitsà ________________________________
2. Formulaà ____________________________________
3. ________________________________________ - speed is increasing
4. _______________________________________ - speed is decreasing
** also known as _________________________________
Practice Problems
1. A car accelerates from rest to 30m/s in 15 seconds. What is its acceleration?
2. A car decelerates from 80 m/s to 40 m/s in 2 seconds. What is its acceleration?
II.
Nature of Forces
A. ________________________________________- a push or pull on an object
1. Can cause an object’s motion to change
2. Unitsà _______________________________________
3. ___________________________àsum (total amount) of forces
a. ________________________ -same size, opposite directions; no movement
happens
b. ________________________ -different size, same/different direction;
movement occurs with this force
B. Newton’s 1st law of motion
1. Also called _________________________________________
2. Law states an object at rest ____________________________and an object
in motion ___________________________unless an _______________________
*Examples
a. pulling off a tablecloth and ______________________________________
b. _______________________________________when a car comes to a stop
C. Newton’s 2nd Law
1. shows the relationship among ________________________________
* The greater the force the greater the acceleration
* Acceleration and mass change opposite of each other
2. Formulaà _____________________________________________
3. Measurement tool à _____________________________________
Practice Problems
1. What force is needed to push your 80 kg friend on a sled at an acceleration of 0.5 m/s2?
2. A student pedaling a bicycle applies a net force of 200 N. The mass of the rider and the
bicycle is 50 kg. What is the acceleration of the bicycle and the rider?
D. Newton’s 3rd Law
1. Statesàfor every action there is an _________________________________
____________________________________________________________
2. Exampleà a rocket fires its engines _____________________________ and the
rocket __________________________________________________
Review of Newton’s Laws of Motion
1. A magician pulls a tablecloth out from under
dishes and glasses on a table without disturbing
them.
Answer:
2. A person’s body is thrown outward as a car
rounds a curve on a highway.
Answer:
3. Rockets are launched into space using jet
propulsion where exhaust accelerates out from the
rocket and the rocket accelerates in an opposite
direction.
Answer:
4. A picture is hanging on a wall and does not move.
Answer:
5. A person not wearing a seatbelt flies through a
car window when someone slams on the breaks
because the person’s body wants to remain in
continuous motion even when the car stops.
Answer:
III.
6. Pushing a child on a swing is easier than pushing
an adult on the same swing, because the adult has
more mass.
Answer:
7. A soccer ball accelerates more than a bowling
ball when thrown with the same force.
Answer:
8. A soccer player kicks a ball with their foot and
their toes are left stinging.
Answer:
9. A student leaves a pencil on a desk and the
pencil stays in the same spot until another student
picks it up.
Answer:
10. Two students are in a baseball game. The first
student hits a ball very hard and it has a greater
acceleration than the second student who bunts
the ball lightly.
Answer:
Friction and Gravity
A. _____________________________ – force of resistance between objects that touch
B. Types of Friction
1. ______________________- objects slide past each other; ex. hockey puck on ice
2. ____________________- objects roll each other; ex. bowling ball going down the lane
3. __________________- caused by gases or liquids; ex. Baseball flying through the air
C. _____________________________ - objects travel in curved paths due to gravity and
inertia
D. ________________________________________ - keeps objects moving in a circle;
ex. Amusement park rides and spinning a bucket of water without spilling it
E. _______________________________ - a force of attraction exists between objects
1. __________________________gives the universe _________________________
2. __________________________– the force of gravity on an object
3. Acceleration due to gravity- _____________________
**All objects fall with the same acceleration regardless of mass
** Air resistance determines how fast something falls, not gravity
IV. Graphing Motion
A. Constant Speed/No Acceleration
B. No Speed/No Acceleration
C. Average Speed/Acceleration
D. Constant Acceleration/Average Speed
E. No Acceleration/Constant Speed
F. Average Acceleration/Average Speed
G. Negative Acceleration/ Average Speed