Lecture 3: 1D Constant Acceleration & Free Fall Questions of Yesterday 1a) Is it possible to have +/- velocity and ZERO acceleration? a) YES b) NO 1b)

Slides:



Advertisements
Similar presentations
Freefall Motion Notes Any object near the surface of the Earth experiences the pull of gravity. If released from rest, the object will fall freely toward.
Advertisements

Motion in One Dimension – PART 2.
Free Fall Projectile Motion – free fall, but not vertical.
Projectile Motion Review Game
Free Fall Student determine the effect of gravity on objects without support. Students will calculate these effects of gravity over time.
One-Dimensional Motion in the Vertical Direction (y – axis) or Freely Falling Bodies Montwood High School Physics R. Casao.
1. 2 FREELY FALLING OBJECTS - we will consider the case where objects move in a gravity field – namely free-fall motion. We will neglect [for a time]
The two measurements necessary for calculating average speed are
1 Projectile Motion. 2 Projectile An object that moves through the air only under the influence of gravity after an initial thrust For simplicity, we’ll.
Motion in One Dimension
Chapter 2 Pretest. 1. After a body has fallen freely from rest for 8.0 s, its velocity is approximately: A) 40 m/s downward, B) 80 m/s downward, C) 120.
Warm - up Problem: A sprinter accelerates from rest to 10.0 m/s in 1.35s. a.) What is her acceleration? b.) How far has she traveled in 1.35 seconds?
Free Fall What did the video show?
Describing Motion: Velocity & Acceleration
Projectile Motion 1.
Free Fall Lecture 3.
Speed, Velocity and Acceleration
Speed, Velocity and Acceleration
Get out paper and something to write with!. On a sheet of paper answer the following questions…you may ask a neighbor. 1. What is gravity? 2. What is.
A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 58.8 m/s in 6 seconds. He then pulls the parachute cord and.
Motion in One Dimension
Motion in One Dimension Unit 1. Lesson 1 : Position, Velocity, and Speed Position : location of a particle with respect to a chosen reference point Displacement.
Units of Chapter 2 Reference Frames and Displacement (2-1) Average Velocity (2-2) Instantaneous Velocity (2-3) Acceleration (2-4) Motion at Constant Acceleration.
Physics of Motion. Frame of Reference- background or object that shows a change in position. Ex. Earth or the Horizon Fixed in place. If an object is.
Linear Motion Unit 1. Motion occurs all around us. Motion is easy to recognize, but it is hard to describe. Even the Greek scientists of more than 2000.
Lecture 5: Vectors & Motion in 2 Dimensions. Questions of Yesterday 2) I drop ball A and it hits the ground at t 1. I throw ball B horizontally (v 0y.
Motion in one dimension
Return to Table of Contents Acceleration What is constant speed? If the speed of an object does not change, the object is traveling at a constant speed.
Acceleration. Review Distance (d) – the total ground covered by a moving object. Displacement (  x) – the difference between an object’s starting position.
Honors Physics Chapter 3
Chapter 3 Review Acceleration and Free Fall 1.When an object undergoes a change in velocity, it is said to be ______________. ans: accelerating/decelerating.
Kinematics in One Dimension We will focus today on problem- solving. Note: some problems are hard, some are not so hard. Part of the learning is recognizing.
 What is the unit we use for speed?  m/s  What is the term for speed and direction?
Graphical Look at Motion: displacement – time curve The slope of the curve is the velocity The curved line indicates the velocity is changing Therefore,
Kinematics Kinematics – the study of how things move
Parabolic or Projectile Motion
1 Chapter 2 Motion F. Morales. 2 CHAPTER OUTLINE  Motion Motion  Vectors Vectors  History of Motion History of Motion  Speed & Velocity Speed & Velocity.
Section 3 Acceleration.
Notes on Motion VI Free Fall A Special type of uniform acceleration.
Chapter 3 Kinematics in Two Dimensions. 3.1 – d, v, & a A bullet is fired horizontally. A second bullet is dropped at the same time and at from the same.
Motion in One Dimension Physics 2053 Lecture Notes 02a dx dt x t Kinematics in One Dimension (Phy 2053) vittitoe.
Unit 3 Kinematics Equations Objectives: Learn the 4 motion equations for 1 dimensional motion when acceleration is constant.
Equations of Motion Review of the 5 Equations of Motion.
Physics for Scientists and Engineers, 6e Chapter 2 – Motion in One Dimension.
 Vertical projectile motion deals with objects that fall straight down, objects that get thrown straight up and the motion of an object as it goes straight.
Test Review Chapter 4 – Linear Motion. Question You’re solving a problem and you see a unit of km/hr. What variable is this giving you?
If your pen falls off your desk does it accelerate? If I drop a pen, what is its initial speed? How fast is it going just before it hits the ground? ZERO.
1 Physics Chapter 2 Motion in One Dimension Topics:Displacement & Velocity Acceleration Falling Objects.
Chapter 2 Motion in ONE dimension. Displacement This chapter we are only doing to study motion in one direction. This chapter we are only doing to study.
You will be able to calculate Instantaneous speed Average speed Of falling or rising objects.
1. The speed of sound in air is 330m/s. In one hour sound could travel a distance of: A. 620 mi B. 743 mi C. 810 mi D mi.
PROJECTILE MOTION NOTES i
Uniform motion The following symbols will be used throughout M1: s u v
Acceleration due to gravity (Earth)
SPH3U Exam Review Equations of Motion.
Physics Support Materials Higher Mechanics and Properties of Matter
Mechanics: Motion in One Dimension x dx Notes by: Ted Vittitoe
3.1 Acceleration How would you describe the motion of the runner in each motion diagram?
A ball is rolling along a flat, level desk. The speed of the ball is 0
Projectile Review.
v = v0 + a ∆t ∆x = v0∆t + 1/2 a∆t2 v2 = v02 + 2a∆x
Free Fall What did the video show?
The vertical one-dimensional motion
Projectile Motion Discussion Questions
In this section you will:
WARM-UP If an object starts at rest and accelerates through a certain distance in a certain amount of time……. How farther would it go if accelerates for.
ACCELERATION.
Uniform Acceleration Review
Velocity and Acceleration
2.7 Freely Falling Bodies In the absence of air resistance, all bodies at the same location above the earth fall vertically with the same acceleration.
Presentation transcript:

Lecture 3: 1D Constant Acceleration & Free Fall

Questions of Yesterday 1a) Is it possible to have +/- velocity and ZERO acceleration? a) YES b) NO 1b) Is it possible to have ZERO velocity and +/- acceleration? a) YES b) NO 2) What is the average velocity in this plot? a) v f b) v f /2 c) between 0 and v f /2 d) between v f /2 and v f t (s) v (m/s) vfvf v f /2 0

Constant Acceleration Motion under Constant Acceleration -> very important All objects on Earth under constant acceleration due to gravity all the time v f - v i t f - t i = a = t (s) v (m/s) vfvf vivi tftf titi

Constant Acceleration Motion under Constant Acceleration -> very important All objects on Earth under constant acceleration due to gravity all the time v f - v i t f - t i = a = t i => 0 t f => t v i = v(t = 0) => v 0 v f => v t (s) v (m/s) v f = v v i = v 0 t f = t t i = 0 = v - v 0 t a

Constant Acceleration: Equations for Motion t i => 0 t f => t v i = v(t = 0) => v 0 v f => v = v - v 0 t a How to determine velocity if you know initial velocity, acceleration and time of motion v = v 0 + at Known Quantities = v 0, a, t Unknown Quantities = v,  x

Constant Acceleration: Equations for Motion How to determine displacement if you know initial velocity, final velocity and time of motion t (s) v (m/s) v v0v0 t0 v+v 0 2 t/2 = v + v 0 2 = xtxt  x = 1/2(v + v 0 )t Known Quantities = v 0, v, t Unknown Quantities =  x, a

Constant Acceleration: Equations for Motion How to determine displacement if you know initial velocity, acceleration and time of motion  x = 1/2(v + v 0 )t v = v 0 + at Known Quantities = v 0, a, t Unknown Quantities =  x, v  x = v 0 t + 1/2at 2

Constant Acceleration: Equations for Motion How to determine velocity if you know initial velocity, displacement, and acceleration of motion  x = 1/2(v + v 0 )t Known Quantities = v 0, a,  x Unknown Quantities = v, t v 2 = v a  x = v - v 0 t a

Practice Problem #1 A Cessna aircraft has a lift-off speed of 120 km/h. a) What minimum constant acceleration does the aircraft require if it is to be airborne after a takeoff run of 240 m? b) How long does it take the aircraft to become airborne?

Practice Problem #2 In the Daytona 500 auto race, a Ford Thunderbird and a Mercedes Benz are moving side by side down a straightaway at 71.5 m/s. The driver of the Thunderbird realizes that she must take a pit stop, and she smoothly slows to a stop over a distance of 250 m. She spends 5.00 s in the pit and then accelerates out, reaching her previous speed of 71.5 m/s after a distance of 350 m. At this point, how far has the Thunderbird fallen behind the Mercedes Benz, which has continued at a constant speed?

Freely Falling Objects Every object on Earth is subject to a constant acceleration due to gravity that pulls it towards Earth g = -9.8 m/s Often convenient to use reference frame with the ground at ZERO, +y away from Earth, -y towards Earth g = -9.8 m/s 2

Free Fall: Concepts & Problem Solving What happens to d during free fall? What happens to v? What happens to a? How does each vary with time? Can use constant acceleration equations of motion with a = g = -9.8 m/s v = v 0 + gt  x = v 0 t + 1/2gt 2 v 2 = v g  x

Free Fall: Concepts & Problem Solving If I throw a ball straight up in the air: By how much does the speed decrease with each second while ascending? By how much does the speed increase with each second while descending? How much time is required for rising compared to falling? Does the distance between 1 s intervals increase, decrease, or stay the same while ascending? Does the distance between 1 s intervals increase, decrease, or stay the same while descending?

Free Fall: Problem #1 If I throw a ball straight up in the air: a) What is the velocity of the ball when it reaches its highest point? b) What is the velocity 1 s before reaching the highest point? c) What is the change in its velocity during this 1 s interval? d) What is its velocity 1 s after reaching its highest point? e) What is the change in its velocity during this 1 s interval? f) What is the change in velocity during the 2 s interval? g) What is the acceleration of the ball during c), e), and f)?

Free Fall: Problem #2 A mountain climber stands at the top of a 50.0 m cliff that overhangs a calm pool of water. She throws two stones vertically downward 1.00 s apart and observes that they cause a single splash. The first stone had an initial velocity of m/s. a) How long after release of the first stone did the two stones hit the water? b) What initial velocity must the second stone have had, given they hit the water at the same time? c) What was the velocity of each stone at the instant it hit the water?

Free Fall: Problem #3 A ball is thrown upward from the ground with an initial speed of 25 m/s. At the same instant another ball is dropped from a building 15 m high. After how long will the balls be at the same height?

Questions of the Day 1)A skydiver jumps out of a hovering helicopter and a few seconds later a second skydiver jumps out so they both fall along the same vertical line relative to the helicopter. 1a) Does the difference in their velocities: a) increase b) decrease c) stay the same 1b) What about the vertical distance between them? 2) I drop ball A and it hits the ground at t 1. I throw ball B horizontally (v 0y = 0) and it hits the ground at t 2. Which is correct? a) t 1 < t 2 b) t 1 > t 2 c) t 1 = t 2