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agasfer [191]
4 years ago
5

Liz rushes down onto a subway platform to find her train already departing. she stops and watches the cars go by. each car is 8.

60 m long. the first moves past her in 1.80 s and the second in 1.66 s. find the constant acceleration of the train.
Physics
1 answer:
Snezhnost [94]4 years ago
5 0

 

The average velocity can be calculated using the formula:

v = d / t

For the 1st car, the velocity is calculated as:

v1 = 8.60 m / 1.80 s = 4.78 m / s

While that of the 2nd car is:

v2 = 8.60 m / 1.66 s = 5.18 m / s

 

Now we can solve for the acceleration using the formula:

v2^2 = v1^2 + 2 a d

Rewriting in terms of a:

a = (v2^2 – v1^2) / 2 d

a = (5.18^2 – 4.78^2) / (2 * 8.6)

a = 0.23 m/s

 

Therefore the train has a constant acceleration of about 0.23 meters per second.

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v_0 = 32 m/s is the initial speed of the projectile, so its components along the x- and y- directions are

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To determine how far the cannonball travelled, we need to find the value of the horizontal position x(t) when the ball hits the ground, at t=4.94 s. Substituting this value into the equation of motion along x, we find:

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The vertical velocity at time t is given by

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y(t)=y_0 + v_{0y}t-\frac{1}{2}gt^2=12+(21.8)(2.22)-(4.9)(2.22)^2=36.2 m

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