Non-Inertial Reference Frames Unit 4 section 6.6 and 6.7

Frames of Reference Watch this masterpiece filmed in Toronto in Frames of Reference Introduction

Inertial Reference Frames An electromagnetic holds up a steel ball. When the current stops, the ball falls due to gravity.

Inertial Reference Frames The electromagnet and stand are mounted on a cart with wheels attached to a track. Predict the trajectory of the marble if 1.The cart is moving at constant velocity on the track while the camera is mounted on the table? 2.The camera and electromagnet are both on the cart moving at constant velocity relative to the table. Link to video (start at 5:45)

Inertial Reference Frames In which frame of reference do Newton’s Laws hold true? Prove this with a force diagram.

Inertial Reference Frames Newton’s Laws of Motion are obeyed in inertial frames of references. Inertial frames of reference move at constant velocity relative to each other. They are all equally valid.

Non-Inertial Reference Frame In this experiment the camera is mounted on the cart with the marble and electromagnet. The cart is them tied to a string with a mass attached. When released, the stand, electromagnetic and marble accelerates to the right. During this period of acceleration, the marble is released. Predict the motion of the marble as captured by the camera on the cart. Link start at 13:15Link start at 13:15

Non-Inertial Reference Frame Draw a diagram of the forces acting on the marble. Can its motion be explained by the forces?

Car Pendulum Draw a force diagram for the pendulum in the video. Compare your diagram with your partner and discuss. Smarter Everyday

Merry Go Round Watch the motion of the puck in the different frames of reference. Draw a force diagram for each frame of reference. In which frame of reference are Newton’s Laws valid? Which frame does a fictitious force appear to be exerted on the puck? Watch the puck

Do Newton’s Laws always apply? Think about the three videos we just watched. Summarize what you witnessed. Did you notice any patterns? Watch this and explain the strange motion of the basketballs.Watch this and explain the strange motion of the basketballs.

Accelerating Reference Frames Examples: a car speeding up, a merry go round spinning, a bus slowing down What is the space station doing? Why does the camera appear to accelerate? Thrust on board the International Space Station

Question 8 A space station has an inner radius of 100 meters and an outer radius of 140 m. The station rotates at one revolution every 20 seconds. What is the apparent weight of a 50-kg person and the apparent gravitational field (a) at X (b) at Y ?

Answer (a) 690 Newtons 13.8 m/s 2 (b)494 Newtons 9.9 m/s 2 On board a rotating space station - DO NOT READ THE TEXT!!! IT IS SO WRONG!!!!

An Experiment Two 1-kg carts are pulled across the track with a force sensor. The Capstone software records the force and speed of the carts vs time. Two graphs show the data on the next page.

Data

Apparent Weightlessness Inside the International Space Station Watch this video of astronauts aboard the International Space Station (ISS). Draw a force diagram of the force(s) acting on the astronaut? Is the force diagram consistent with the motion? What is the apparent value of the acceleration due to gravity? Then, calculate the value of the acceleration due to gravity, g, at the ISS’s height (350 km) above the earth’s surface. How do you explain the discrepancy?

Example A scientist in the International Space Station experiences apparent weightlessness because (A) there is no gravitational force from the Earth acting on her. (B) the gravitational pull of the Moon has canceled the pull of the Earth on her. (C) she is in free fall along with the Space Station and its contents. (D) at an orbit of 200 miles above the Earth, the gravitational force of the Earth on her is 2% less than on its surface. (E) in space she has no mass. Angry Birds & Pigs in Space