Case 1:
train starts from rest (u = 0)
accelerates uniformly at = 2 m/s² ( a = 2)
for 10 s (t = 10s)
Case 2:
Train maintains constant speed for 200 s
Case 3:
breaks are applied , and uniformly retarded
comes to rest in 50 s.
i) Maximum velocity reached
ii) Retardation in last 50 s
iii)Total distance travelled
iv) Average velocity of train
I) In case 1:
u = 0 , a = 2 m /s² , t = 10 s
to find :
v (final velocity)
we know that,
by putting the values
v = 0 + 2 × 10
v = 20 m/s
in case 2:
the train maintains constant speed so velocity = 20 m/s
in case 3:
v = 0 (as it comes to rest)
therefore maximum velocity = 20 m/s
ii) u = 20 m/s , v = 0 , t = 50 s
v = u + at
0 = 20 + 50 a
20 = -50 a
* Note - negative sign means it is retardation .
iii) We know that,
constant speed for 200 s
We know that - acceleration = 0 , when velocity is constant .
therefore , u = 20 m/s , a = 0 , t = 200 s
u = 20 m/s , v = 0 , a = -0.4
We know that,
v² = u² + 2as
0² = 20² + 2(-0.4) s
0 = 400 -0.8 s
400 = 0.8 s
therefore ,
total distance = 100 + 4000 + 500 = 4600 m .
iv). Average speed =
Answer:
I did (i) & (iii)
Mark the above answerer as brainliest as she did all
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Verified answer
★ Given :
Case 1:
train starts from rest (u = 0)
accelerates uniformly at = 2 m/s² ( a = 2)
for 10 s (t = 10s)
Case 2:
Train maintains constant speed for 200 s
Case 3:
breaks are applied , and uniformly retarded
comes to rest in 50 s.
★ To find :
i) Maximum velocity reached
ii) Retardation in last 50 s
iii)Total distance travelled
iv) Average velocity of train
★ Solution :
I) In case 1:
u = 0 , a = 2 m /s² , t = 10 s
to find :
v (final velocity)
we know that,
by putting the values
v = 0 + 2 × 10
v = 20 m/s
in case 2:
the train maintains constant speed so velocity = 20 m/s
in case 3:
v = 0 (as it comes to rest)
therefore maximum velocity = 20 m/s
ii) u = 20 m/s , v = 0 , t = 50 s
v = u + at
0 = 20 + 50 a
20 = -50 a
* Note - negative sign means it is retardation .
iii) We know that,
in case 2:
constant speed for 200 s
We know that - acceleration = 0 , when velocity is constant .
therefore , u = 20 m/s , a = 0 , t = 200 s
in case 3:
u = 20 m/s , v = 0 , a = -0.4
We know that,
v² = u² + 2as
by putting the values
0² = 20² + 2(-0.4) s
0 = 400 -0.8 s
400 = 0.8 s
therefore ,
total distance = 100 + 4000 + 500 = 4600 m .
iv). Average speed =![\frac{Total\: distance}{Total\:time\:taken} \\ \\ \\ = \frac{4600}{10 + 200 + 50} \\ \\ \\ = \frac{\cancel{4600}}{\cancel{260}} = 17.69 \\ \\ \\ \bold{Average\:speed = 17.69 m/s } \frac{Total\: distance}{Total\:time\:taken} \\ \\ \\ = \frac{4600}{10 + 200 + 50} \\ \\ \\ = \frac{\cancel{4600}}{\cancel{260}} = 17.69 \\ \\ \\ \bold{Average\:speed = 17.69 m/s }](https://tex.z-dn.net/?f=%20%5Cfrac%7BTotal%5C%3A%20distance%7D%7BTotal%5C%3Atime%5C%3Ataken%7D%20%5C%5C%20%5C%5C%20%5C%5C%20%3D%20%5Cfrac%7B4600%7D%7B10%20%2B%20200%20%2B%2050%7D%20%5C%5C%20%5C%5C%20%5C%5C%20%3D%20%5Cfrac%7B%5Ccancel%7B4600%7D%7D%7B%5Ccancel%7B260%7D%7D%20%20%3D%2017.69%20%5C%5C%20%5C%5C%20%5C%5C%20%5Cbold%7BAverage%5C%3Aspeed%20%3D%2017.69%20m%2Fs%20%7D)
Answer:
I did (i) & (iii)
Mark the above answerer as brainliest as she did all