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Lesson 10 – Forces and FBD’s. August 13, 2013. Learning Goals. The student will be able to identify forces The student will be able to analyze forces acting on a body, with the use of FBD The student will use rectangular components to find the resultant force. Further Explanations.
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Lesson 10 – Forces and FBD’s August 13, 2013
Learning Goals • The student will be able to identify forces • The student will be able to analyze forces acting on a body, with the use of FBD • The student will use rectangular components to find the resultant force
Further Explanations • Physics Classroom: Relative Velocity • A Plus Physics: • Relative Velocity and Riverboat Problems • The Plane and the Wind
Ferry Boat A large ferry boat is moving north at 4.0 m/s [N] with respect to the shore, while a child is running on the deck at a speed of 3.0 m/s. Determine the velocity of the child relative to Earth when the child is running in the following directions with respect to the deck of the boat: (a) north (b) south (c) east
Cruise Ship A group of people on vacation on a cruise ship decide to go up to the top floor. Some decide to take an elevator, which moves at 2.0 m/s, while others climb the stairs at 2.0 m/s. The stairs are at an angle of elevation of 388 up from the east direction. The boat is cruising at a velocity of 3.2 m/s [E] relative to the water. • Calculate the velocity of the people in the elevator relative to the water. • Calculate the velocity of the people taking the stairs relative to the water.
Peer Instruction With Forces • What is a force? • What is the SI unit that measures force? • Newton • Kilogram • Gram • Metre • What is the value of 1 Newton as a unit of force? • 1 kg m2/s2 • 1 kg m/s2 • 1 kg m/s • 1 kg m s2
Contact vs. Non-contact Forces • Distinguish between contact and non-contact forces? • Which of the following is an example of a non-contact force? • A man pushing on piano • Gravity pulling on a bowling ball • A horse pulling a sled • All of the above
Force of Gravity • What is the force of gravity?
Normal Force Professor David Harrison Physics at University of Toronto • What is a normal force? • A book is at rest on a desk. Which statement is true? • The normal force balances the force of gravity • The normal force and gravity both point downwards • Gravity is the only force acting on the book • The normal force is the only force acting on the book
Tension Force • What is the tension? • A force between two colliding objects such as a puck and a hockey stick • Measured using a beam balance • A pushing force exerted by a string or rope • A pulling force exerted by a string or rope • How does a frictionless pulley affect tension? Professor James Fraser Physics at Queens University
Required Before Next Class • Read Section 2.1 • Read Section 2.2 • Complete Relative Motions Questions