Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. ...
-
Upload
rosaline-knight -
Category
Documents
-
view
220 -
download
3
Transcript of Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. ...
![Page 1: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/1.jpg)
Freefall
![Page 2: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/2.jpg)
Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was
max, same as that of the falling object. When air resistance was negligible, all objects
fell with the same unchanging acceleration.
Acceleration
![Page 3: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/3.jpg)
Falling under the influence of gravity only - with no air resistance
Freely falling objects on Earth accelerate at the rate of 10 m/s/s, i.e., 10 m/s2 (more precisely, 9.8 m/s2).
Free Fall
![Page 4: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/4.jpg)
The greater the mass of the object… the greater its force of attraction toward the
Earth. the smaller its tendency to move i.e., the greater
its inertia.
Free Fall
So, the acceleration is the same.
It is equal to the acceleration due to gravity: 10 m/s2
(precisely 9.8 m/s2).
![Page 5: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/5.jpg)
When acceleration is g—free fall Newton’s second law provides an
explanation for the equal accelerations of freely falling objects of various masses.
Acceleration is equal when air resistance is negligible.
Acceleration depends on force (weight) and inertia.
Free Fall
![Page 6: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/6.jpg)
The velocity acquired by an object starting from rest is
Free Fall—How Fast?
So, under free fall, when acceleration is 10 m/s2, the speed is• 10 m/s after 1 s.• 20 m/s after 2 s.• 30 m/s after 3 s.And so on.
Velocity acceleration x time
![Page 7: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/7.jpg)
The distance covered by an accelerating object starting from rest is
Free Fall—How Far?
So, under free fall, when acceleration is 10 m/s2, the distance is• 5 m after 1 s.• 20 m after 2 s.• 45 m after 3 s.And so on.
Distance (1/2) x acceleration x time x time
![Page 8: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/8.jpg)
A. also 40 m/s.B. 45 m/s. C. 50 m/s.D. None of the above.
At one instant, an object in free fall has a speed of 40 m/s. Its speed 1 second later is
Free FallCHECK YOUR NEIGHBOR
![Page 9: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/9.jpg)
A. also 40 m/s.B. 45 m/s. C. 50 m/s.D. None of the above.
Comment:We assume the object is falling downward.
At one instant, an object in free-fall has a speed of 40 m/s. Its speed 1 second later is
Free FallCHECK YOUR ANSWER
![Page 10: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/10.jpg)
Terminal speed occurs when acceleration terminates
(when air resistance equals weight and net force is zero).
Terminal velocity same as terminal speed, with direction
implied or specified.
Non-Free Fall
![Page 11: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/11.jpg)
A skydiver jumps from a plane. Weight is the only force until air resistance
acts. As falling speed increases, air resistance on
diver builds up, net force is reduced, and acceleration becomes less.
When air resistance equals the diver’s weight, net force is zero and acceleration terminates.
Diver reaches terminal velocity, then continues the fall at constant speed.
Non-Free Fall—Example
![Page 12: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/12.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough information.
As the skydiver falls faster and faster through the air, air resistance
Non-Free FallCHECK YOUR NEIGHBOR
![Page 13: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/13.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough information.
As the skydiver falls faster and faster through the air, air resistance
Non-Free FallCHECK YOUR ANSWER
![Page 14: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/14.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough information.
As the skydiver continues to fall faster and faster through the air, net force
Non-Free FallCHECK YOUR NEIGHBOR
![Page 15: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/15.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough information.
As the skydiver continues to fall faster and faster through the air, net force
Non-Free FallCHECK YOUR ANSWER
![Page 16: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/16.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough
information.
As the skydiver continues to fall faster and faster through the air, her acceleration
Non-Free FallCHECK YOUR NEIGHBOR
![Page 17: Galileo increased the inclination of inclined planes. Steeper inclines gave greater accelerations. When the incline was vertical, acceleration was.](https://reader035.fdocuments.net/reader035/viewer/2022062515/56649d0a5503460f949dcee9/html5/thumbnails/17.jpg)
A. increases.B. decreases. C. remains the same.D. Not enough information.
As the skydiver continues to fall faster and faster through the air, her acceleration
Non-Free FallCHECK YOUR ANSWER
CommentIf this question were asked first in the sequence of skydiver questions, many would answer it incorrectly. Would this have been you?