A car of mass 1000kg travelling at 72m/h is uniformly bought to rest over a distance of 40m. find the average acceleration and the average breaking force.
Answers
Answer:
Answer:
Acceleration is -5 m/s²
\rule{200}{0.5}
\underline{\underline{\mathfrak{Step-By-Step-Explanation :}}}
Step−By−Step−Explanation:
Given :
Mass of car (m) = 1000 kg
Initial velocity (u) = 72 km/h = 20
Final velocity (v) = 0 km/h
Distance (s) = 40 m
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To Find :
Acceleration
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Solution :
Use 3rd equation of motion :
\begin{gathered}\large{\boxed{\sf{v^2 \: - \: u^2 \: = \: 2as}}} \\ \\ \implies {\sf{0 \: - \: 20^2 \: = \: 2 \: \times \: a \: \times \: 40}} \\ \\ \implies {\sf{-400 \: = \: 80a}} \\ \\ \implies {\sf{a \: = \: \dfrac{-400}{80}}} \\ \\ \implies {\sf{a \: = \: -5}} \\ \\ \underline{\sf{\therefore \: Acceleration \: is \: -5 \: ms^{-2}}}\end{gathered}
v
2
−u
2
=2as
⟹0−20
2
=2×a×40
⟹−400=80a
⟹a=
80
−400
⟹a=−5
∴Accelerationis−5ms
−2