Secondary Mechanics/Page2: Linear Motions

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In order to measure a movement, we need one The local difference is then delta x: $$\Delta x$$ = x2 - x1
 * coordinate of location x and one
 * coordinate of time t.

(Local coordinate at the end minus local coordinate at the beginning of the time interval)

Correspondingly the time interval $$\Delta t$$: $$\Delta t$$ = t2 - t1

Thus the speed becomes

v = $$\frac{\Delta x}{\Delta t}$$ (distance through time)

Note: This is a quotient out of differences,

If we take two neighbouring measuring points, then we get the momentary speed of the cart tum to time t1 and/or, we take first and the 51 to t2. , We get the average speed in the time interval to measuring point $$\Delta t$$ = t51 - t1 The movement can be represented graphically in a time-location diagram (t-x-diagram):



Task 1.3: snail mail
Two snails move uniformly and upright in a garden:

The first snail moves with 1 mm / s, the second in 2 s by 4 mm.

After 2 s and remains the second but suddenly snail.

If the first snail second outdated, they doubled their speed, while the second half with early speed creeps.  a) Draw a common x-t-diagram! (1s = 1 cm ; 1 mm = 1 cm)

b)Represent the dependence of the speeds of the time for both movements in a diagram!

(1 s = 1 cm; 0,5 mm/s = 1 cm.)

Tip

Solution

Task 1.4: driving styles
A distance of 300 km is in a car back. Calculate the time needed to when
 * a) the speed of 75 km / h,
 * b) one half of the road at 50 km / h, the other with 100 km / h retired,
 * c) half the journey time of 50 km / h, the other with 100 km / h driven. (Solution for example by guessing and subsequent graphical or computational review!)
 * d) a third of the running time with 66 km / h, two-thirds of 87 km / h back! (Note: Creative Problem Solving needed: either algebraically about solving equations with 2 2 unknowns, or graphically with accounting review of the solution! )

Draw on each sub-task also a time-location-diagram! (100 km = 5 cm, 1 h = 4 cm) Solution

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