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olya-2409
16 days ago
8

A child runs at speed vc while an adult runs at speed va. if the adult gives the child a head start of distance d, how long will

it take for the adult to catch the child? express your answer in terms of va and vc and
d.
Physics
1 answer:
ValentinkaMS [1.1K]16 days ago
4 0
The child runs at speed vc.
The adult runs at speed va.
<span>The adult allows the child a lead of distance d. 
Speed is calculated by distance divided by time: speed = distance/time.
To find the time it takes for the adult to catch the child, use time = d/v.
</span>Let tc be the child's time and ta the adult's time.
tc = D/vc, with D = D + d, so D + d = tc × vc, therefore D = tc × vc - d.
ta = D/va, where D = ta × va.
Equating both: tc × vc - d = ta × va
Thus, ta = (tc × vc - d) / va
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v_f = 13m/s + 0.75 \frac{m}{s^2} * 16 s= 13 m/s +12m/s = 25 m/s

Explanation:

In this scenario, we determine the initial velocity as follows:

v_i = 7 \frac{m}{s}

The final velocity in this instance can be expressed as:

v_f = 13 \frac{m}{s}

It is noted that transitioning from 7m/s to 13m/s takes 8 seconds. We can apply a specific kinematic equation to find the acceleration for the first part of the journey:

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Solved for acceleration, we find:

a = \frac{v_f -v_i}{t} = \frac{13 m/s -7 m/s}{8 s}= 0.75 \frac{m}{s^2}

For the subsequent route, we assume constant acceleration and that the train continues for 16 seconds, beginning with an initial velocity of 13m/s from the previous segment, allowing us to calculate the final speed via the following formula:

v_f = v_ i +a t

Substituting into the equation yields:

v_f = 13m/s + 0.75 \frac{m}{s^2} * 16 s= 13 m/s +12m/s = 25 m/s

5 0
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Which model is used to describe the interaction of external forces that affect an organization's strategy and ability to compete
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Competitive forces model

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Setting up the force equilibrium for the configuration:

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F=126339.5N

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To calculate Fw, we can use:

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F=126339.5N

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9 days ago
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