Word Problems - Kinematics | Show Me The Physics

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Review - drag and drop the runners on the track to show constant velocity and acceleration

Fill In The Blanks Notes

Review

Drag and drop the runners on the track below to show:
a) constant velocity b) acceleration

Drag and Drop Displacement

Video Instruction

showmethephysics.com

Problem-Solving Strategy

E. Solving Problems Using the Motion Equations

Ex 3

Given

Starting from rest, an object accelerates at a rate of 12 m/s².
Find: the velocity of the object at the end of 3.0 seconds.

↓

V_i = 0 a = 12 m/s² t = 3.0 sec

a = (V_f − V_i)/t → 12 m/s² = (V_f − 0)/3.0 sec

V_f = 36 m/s

Motion map showing velocity at each second

Motion Map — 1st sec / 2nd sec / 3rd sec: 12 m/s / 24 m/s / 36 m/s

Ex 4

Tip: underline the given information in the problem.

Given

An object at 100. m/s accelerates at a rate of 120. m/s².
Find: the velocity of this object after .100 seconds.

↓

a = (V_f − V_i)/t → 120. m/s² = (V_f − 100. m/s)/.100 s

Cross Multiply: 12.0 = (V_f − 100.)

V_f = 112 m/s

3 Ways to Have Non-Zero Acceleration

(to change velocity)

F. Motion Terms and Direction

A whole branch of mathematics is required to deal with numbers that have direction: Trigonometry. This is why it is important to know which motion information has direction.

Vector

A quantity that includes magnitude (a number) & direction.

ex) displacement, acceleration, velocity

Scalar

A quantity that includes magnitude (a number) only.

ex) time, distance, speed

Enrichment: Invisible Flame

Relight a Candle from Afar

Video

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Motion Plots II →