Kinematics - 1 - Uniform Motion | High School

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High School
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High School Physics
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2024
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Kinematics (Quantum Ch 9) Uniform Motion, Velocity & Speed 3.0 Uniform Motion:  If both speed & direction remain the same; velocity is constant (vertical or horizontal)  Ex. an elevator (vertical), or a vehicle in cruise control (horizontal) 3.1 Speed: Is the distance covered by an object in a unit of time  Scalar quantity  The speed and velocity of an object may have the same magnitude but, of course, velocity will have a direction and speed will not. v = speed  d v= t ∆d = distance ∆t = time 3.2 Velocity: Is the displacement of an object in a unit of time  Rate of change of position  Vector quantity    d v= t v = velocity ∆d = displacement ∆t = time Ex #1 Jamaican sprinter Usain Bolt ran 100.0 m in 9.58 seconds at the 2009 World Championships. Assuming uniform motion, what was his speed in m/s? km/h? d v= t 100.0m v= 9.58s 0.1000km v= 0.00267h v = 10.4m / s v = 37.6km / h Ex #2 An air traffic controller notices that an aircraft has a velocity of 360.0km/h [SW]. What displacement will the plane have after 25 seconds?   d v= t  d 360 = 0.00694  d = 2.5km[SW ] Ex #3 A car travels from a position of 2.0km [N] to a position of 20.0km [S] in 30.0 min. What is the car’s velocity in km/h?   d v= t  22.0km[ S ] v= 0.5 00h  v = 44.0km / h[ S ] Ex #4 A student leaves school at 4:00pm. He is eager to get home and start writing his physics lab report. He starts to jog at a steady rate of 3.0m/s, towards his home, 2.0km away. His lab partner leaves school five minutes later on her bike, follows the same route at 7.0m/s. What time is it when she catches up with her partner? When she catches up, both have traveled the same distance. But she has traveled 300s less! distance traveled time y = ax + b initial value = distance “started” at speed y = ax + b y = 3x y = ax + b y = 7( x − 300) y = 7 x − 2100 Let x be the time traveled by the first student. y = 3x y = 7 x − 2100 3x = 7 x − 2100 x = 525s 8 min 45 sec They meet at 4:08:45 Homework: pg 213 #1, 2, 3, 4 Quantum