Download presentation

1
270 34 N 13 N 510 2/ 1 cm:2N 1/ 1 cm:5N

2
1 cm:10 N 42N 1 cm:4 N 10 N 200 460 6.5 cm 26N 4.2 cm 42N 1 cm:3 N 1 cm:8 N Fx = 0 Fx = 40 N Fy = 0 Fy = -6 N

4
**Newton’s 1st Law of Motion:**

If the ____________________ force, Fnet, acting on an object equals ________, then that object has ____________________ . Its acceleration a = _____ . It is said to be in __________________ . net (resultant) zero constant velocity equilibrium Because forces are ______________ and have ____________ , the x and y _______________ of the forces often must be added up _______________ when there are forces along different _________. vectors direction components separately axes net Fx ________ = 0 Fnet = 0 really means: net Fy ________ = 0

5
**Ex: A 20-N box at rest on a table being pushed down with a 5 N force.**

Free body diagrams: Ex: A 20-N box on a table at rest FN = 20N 20-N w = FN "At rest" __________ w = 20 N Ex: A 20-N box at rest on a table being pushed down with a 5 N force. 5-N FN = 25 N 20-N 5 N w + push = FN w = 20 N "At rest" _______________ Both of these boxes are in ___________________ . equilibrium

6
**Ex: Same box sliding to the right on a horizontal **

frictionless table at a constant velocity 2.0 m/s v = 2.0 m/s FN = 20N 20-N w = 20N "constant velocity" __________ w = FN velocities Draw only the __________ , not the ____________ forces Notice: 1/ The free body diagram is the _________ as the first example. Both are in ___________________ . 2/ No force is ___________ to keep box moving. The box will continue its motion ________________. same equilibrium needed forever

7
**Ex: The forces acting on a 20-N box are shown at right:**

FN = 20N pull = 10N Ff = 10 N w = 20 N This box is in ___________________. It is either: 1/ _____________ (constant velocity = _____); 2/ or _____________ at a constant velocity. equilibrium at rest moving Unless other information is given, it is _______________ to tell if it is at rest or moving. impossible

8
**Ex. The three forces below are the only ones **

acting on an 2.0-kg object. What is the acceleration of the object? Add them up: 3.0 N 4.0 N 5.0 N 3.0 N 5.0 N 4.0 N The net force Fnet = _____ so a must = ____ . This object could be _______________ or moving with ____________________________ . at rest constant velocity

9
**If an object is ____________ or moving with **

Restatement of 1st Law: If an object is ____________ or moving with _____________________, it is_________________. Then the net force (Fnet ) acting on it _________ . at rest constant velocity in equilibrium = 0 Ex: A B-2 bomber flying at constant velocity: lift = 1.3 MN Ff (drag) = 300 kN thrust = 300 kN weight ≈ 1.3 x 106 N thrust ≈ 75 x 103 N/engine x 4 engines w= 1.3 MN

10
The “air force”

11
**Ex. The two forces shown below act on an **

object. What third force is needed to produce equilibrium? F1 F2 First way to solve: Find resultant force F The answer is -F: F -F balances -F ___________________ the other two forces.

12
**Add the two forces using head to tail method. **

Second way to solve: Add the two forces using head to tail method. Add a force to "bring the total force to zero." original head to tail: F1 F2 F1 -F F2 Notice: Both ways give ________________________ -F is NOT the ________________ of the other vectors. It is the force that ________________ the other vectors, making Fnet =________. It is sometimes called the ________________ because it is what is needed to produce ___________________ . the same result resultant "balances out" equilibrant equilibrium

13
**Ex. Draw the vector that represents the force **

that the beam exerts on point A. beam force wire T A A beam building weight w The beam force is the ________________ . It must be added to the other forces so that ___________ equilibrant Fnet = 0

14
**Ex. Increasing angle between 2 wires supporting a picture:**

5 1 2 1 2 T = ____ in each wire Case 1: vertical wires 10 N w = 10 N 7 T = ____ in each wire 1 2 2 1 Case 2: greater angle 10 N w = 10 N Case 3: even greater angle T = ____ in each wire 10 1 2 2 1 10 N w = 10 N increases As q increases, the tension _______________ .

15
**A net force is ________________ to maintain **

motion. An object will maintain its motion in the ________________ of a net force. This idea was discovered by _____________. An object in motion tends to ____________________ , and an object at rest tends to _________________ . The _______________________ that “makes” this true is called its ___________ . not needed absence Galileo stay in motion stay at rest property of matter inertia Ex. What has more inertia, a truck or a baseball? truck inertia more __________ more___________ mass inertia mass

16
**Inertia is the tendency of an object to **

_________________________ . More inertia (mass) means it is __________________ for an object to… 1/ …_____________________ when it is at rest; 2/ … __________ when it is already moving; and, 3/ … ____________________ from a straight path. In other words, ______________ is why an object needs __________________ to maintain its motion. This is why Newton's _____________ is called the ________________ . resist changes in motion more difficult start moving stop move sideways inertia no net force equilibrium Law of Inertia 1st Law Law of Inertia Fnet a = 0 = 0

17
**Open your 3-ring binder to the Worksheet Table of Contents. **

Record the title of the worksheet: Newton’s First Law WS

Similar presentations

OK

WHAT IS A FORCE????? PUSH A force is a push….. PULL … or a pull.

WHAT IS A FORCE????? PUSH A force is a push….. PULL … or a pull.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on new technology in mechanical Ppt on google driverless cars Ppt on different types of forests in the us Free ppt on brain machine interface ethics Ppt on channels of distribution of pepsi Topics for ppt on environmental issues Eat before dentist appt on saturday Ppt on autonomous car news Moving message display ppt on tv Ppt on artificial intelligence in power station