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3 years ago

(ii) Describe how the acceleration of the train at time t = 100 s differs from the acceleration

Physics

1 answer:

quester [9]3 years ago

7 0

Explanation:

Acceleration is the rate of change of velocity with time. When acceleration increases a body moves a faster velocity.

In the graph acceleration at time t= 100s is rapidly increasing.
At t = 20s, the acceleration of the body is getting started up.

A vehicle at time 100s will have a faster velocity compared to one at t = 20s

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Answer:

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$KE_T + PE_T = KE_B + PE_B$

Where $KE_T$ is the kinetic energy of the person before jumping which equal to zero(because to kinetic energy at maximum height )

and $PE_T$ is the potential energy of the before jumping which is mathematically represented at

$PE_T = mg H$

and $KE_B$ is the kinetic energy of the person just before landing on the safety net which is mathematically represented at

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and $PE_B$ is the potential energy of the person as he lands on the safety net which has a value of zero (because it is converted to kinetic energy )

So the above equation becomes

$mgH = \frac{1}{2} m v^2$

=> $v = \sqrt{2 gH }$

substituting values

$v = 16.57 m/s$

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$v_f = v + 2 a s$

Now the final velocity is zero because the person comes to rest

$0 = 16.57 + 2 * a * 1.8$

$a = - \frac{16.57^2 }{2 * 1.8}$

$a = - 76.27 m/s^2$

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3 years ago