Question

A trick is moving with v= 36km/hr is stopped by breaks after 2sec. If same trick moves with speed 144km/fr find stopped time

Answer 1

Correct question:

A truck is moving with v= 36km/hr is stopped by breaks after 2sec. If same truck moves with speed 144km/hr find stopping time.

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Given:

• u1= 36km/hr
• u2= 144km/hr
• v1 = 0 m/sec
• v2= 0 m/sec
• t1= 2sec

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Need to find:

• t2=?

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Solution:

u1= 36km/hr

$\rightarrow \: u = 36 + \dfrac{5}{18} m/s$

→ u= 10m/sec

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u2= 144km/ hr

→ u2= $144 \times \dfrac{5}{18} m/s$

→u2 = 40m/sec

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We know,

Stopping time = $\dfrac{ - u}{a}$

Thus,

→$2 = \dfrac{ - 10}{a}$

→$a = - 5m/ {sec}^{2}$

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For t2:

Time = $\dfrac{ - u}{a}$

→t2= $\dfrac{ - 40}{ - 5}$

→$\red{\bold{\boxed{\large{{t}_{2}= 8}}}}$

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The stopping time is 8 seconds.