# Measuring Acceleration How To Measure Acceleration UmmmIsnt that thing in the bag an accelerometer? How does that tube thing work? Its called an accelerometer, but it doesnt really measure acceleration. 3 2 1 0 1

2 3 3 A clue to what it measures 2 Turn the tube so that it is vertical. Now it is measuring along the head-to-toe axis. When you stand motionless, the tube looks like this: What does that reading of 1 mean? Draw a force diagram for a person

standing motionless. (2) How big is the normal force on the person by the floor compared to the force of gravity on the person by the earth? (3) 1 0 1 2 3 3 Are you correct? FNPS 2 1

0 1 FGPE 2 3 A Simple Confirmation of what that device tells you Stand still. Hold the tube so that one end points directly in front of you. The device is now measuring along the front-to-back axis. The tube looks like this: 2 1 1

2 On 3your force diagram for0 a person standing 3 motionless, how big is the force pushing forward or backward on the person compared to the force of gravity on the person? (4) Are you correct? FNPS FGPE 3

2 1 0 1 2 3 A more correct name than Accelerometer The device is actually a Force Factor Meter. The reading on the device will tell you the size of a

push or pull force on you compared to the size of the force of gravity on you. The key to using it correctly is understanding which force it is measuring. After obtaining the force factor readings, acceleration can be found by examining a force diagram. Easy example: On Mr. Freeze, a 45 kg rider speeds up while moving to the right. Predict the direction of movement on the force factor meter. (5) 3 2

1 0 1 2 3 Example (continued) The force factor meter looks like this while the rider accelerates. Draw a force diagram for the rider. (6) Check your neighbor! SF a v

Are you correct? FNPS FPPS FGPE 3 2 1 0 1 2

3 Find the acceleration! The riders mass is 45 kg. How much does the rider weigh? (7) The force factor meter reads 2.2. How big is the forward push on the person by the seat? (8) What is size of the net force acting on the person? (9) What is the persons acceleration? (10) Bonus! Heythe guy sitting next to this rider had a mass of

90 kg. What do you think his force factor meter read? (11) Tougher example 3 On the Screamin Eagle, a 45 kg rider goes over the crest of a hill. The FF meter is held on the head-to-toe axis. Predict the reading on the meter. (12) 2 1 SF

0 a 1 v 2 Draw a force diagram for the rider. (13) 3 3 Are you correct? 2 1 0

FGPE Can you calculate the net force on the rider? The acceleration of the rider? 1 2 3 3 2 OMG example 1 SF 0

a 2 down at the top of a loop. The FF meter is held on the head-to-toe axis. Predict the reading on the meter. (14) Draw a force diagram for the rider. (15) 3 On the Ninja, a 45 kg rider goes upside- 1 v

3 1 0 1 2 Frame of Reference Check 3 inverted point of view, the FF meter is moving down towards his lap. So this FF reading is for a force directed which way? (16)

2 Before we go on, notice that from the riders Are you correct? FGPE 3 2 1 FNPS 0 1 Can you calculate the net force on the rider? The acceleration of the rider?

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