A body accelerates uniformly from rest at \(6 ms ^{-2}\) for \(8 sec -\) onds and then decelerates uniformly to rest in the next 5 seconds. The magnitude of the deceleration is ____________
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Correct Answer: Option A
Explanation:
Given: \(a=6 ms ^{2}, t_{1}=8 sec , t_{2}=5 sec\).
\(u=0, v=u+a t, v=a t\)
\(v=6 \times 8=48 m / s\)gain, \(v=u+a t\)
When the car decelerates to rest,
\(v=0, u=48 m / s . v=u+a t\)
\(0=48+a \times 5\)
\(a=\frac{-48}{5}=-9.6 m / s ^{2}\),
Hence the deceleration is \(9.6 m / s ^{2}\)
Given: \(a=6 ms ^{2}, t_{1}=8 sec , t_{2}=5 sec\).
\(u=0, v=u+a t, v=a t\)
\(v=6 \times 8=48 m / s\)gain, \(v=u+a t\)
When the car decelerates to rest,
\(v=0, u=48 m / s . v=u+a t\)
\(0=48+a \times 5\)
\(a=\frac{-48}{5}=-9.6 m / s ^{2}\),
Hence the deceleration is \(9.6 m / s ^{2}\)