# In Motion: A Physics Unit I love physics, but I hate moving.

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In Motion: A Physics Unit I love physics, but I hate moving.

Rearranging equations: Used to find an unknown value. Goal is to get only the unknown alone on one side of the equation. One rules for moving variables around: “Moving a variable ACROSS the equal sign CHANGES the OPERATION.”

Move variables that are multiplied or divided: “Moving ACROSS the equal sign CHANGES the OPERATION.” = V1V1 V2V2 T2T2 T1T1 4 = H 2 2 x 4 = H 8 = H

Move variables that are added or subtracted: “Moving ACROSS the equal sign CHANGES the OPERATION.” = V1V1 d f + a - a - 24 = x 4 + 2 = x 6 = x

= 2x P + T- T = (a)(F)P (T)

y = x + bm y – b = mx y – b = m x m = y – b x = 8 4 4 = 8 A A x 4 = 8 A = 2

Speed or Velocity

Speed is how fast an object moves. Speed is scalar. It has a size but no direction. The symbol for speed is v The units of speed can be km/h OR m/s or cm/min

Speed is calculated as the total distance travelled over the total time it took to travel This is actually the average speed. v = Δd t distance time interval

If you travel from Winnipeg to Flin Flon, a distance of 700 km in 7 hours, your speed is? v = 100 km/h v = ΔdΔd t 700 km 7 h

How long did it take a person driving 50 km/h to go a distance of 300 km? Δd = 300 km t = ? v = 50 km/h t = 300 km 50 km/h t = 6 h = Δd v v = Δd Δd t t x v = Δd t

1 h 60 min 1 min 60 s A skate boarder moves at a speed of 5 m/s, how far does he go in 1 hour? Δd = ?t = 1 h v = 5 m/s 5 = Δd Δd 3600 3600 x Δ d = 18000 m v = Δ d t Your units always have to match. 1 h xx = 3600 s

Velocity measures a change in position with time. Velocity is a vector quantity. (SPEED is total distance over time) Velocity is calculated as displacement over time. v = d t

If you travel from Winnipeg to The Pas, displacement of 420 km [south]. The trip takes 4.00 hours. Velocity is: 105 km/h[south] v = 420 km[south] 4.00 h v = d t ∆d = 420 km [s] ∆t = 4.0 hr v = ?

A car with a velocity of 20 m/s north, traveled for 60 seconds, what was the displacement? ∆d = ? ∆t = 60 s v = 20 m/s [N] ∆d = 1200 m [N] ∆d = 60 s x 20 m/s [N] v = Δd Δd t t x v = Δd

If the stickman below takes 2 seconds to walk, calculate distance, displacement, speed, velocity: 11 cm 6 cm Δd = 11 + 6 + 11 Δd = 28 cm ∆d = d 2 - d 1 ∆d = 6 cm - 0 cm ∆d = 6 cm (down) ∆t = 2 s

11 cm 6 cm Δd = 28 cm ∆d = 6 cm (down) v = Δd t v = d t t = 2 s v = 28 cm 2 s v = 14 cm/s v = 6 cm (down) 2 s v = 3 cm/s (down)

d = d 2 - d 1 v = d t v = Δ d t t = t 2 - t 1

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