Question

find the initial velocity of a car which stops in 10 sec after applying brakes at the rate of 2m/s2

Answer 1

u = ?
v = 0
t = 10s
a = -2 m/s²

v = u +at
⇒ 0 = u + (-2)×10
⇒ 0 = u - 20
⇒ u = 20 m/s

Initial velocity was 20 m/s

Answer 2

Heya......!!!

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This question can be easily solved by applying equation of motion .

Given in the question :-

• Final velocity ( v ) = 0
• Time. ( t ) = 10 sec
• Acceleration ( a ) = -2 m/s^2. ( -ve sign indicates retardation .

So , by applying the equation ' v = u + at ' we can take out initial velocity ( u ) .

Putting the values we get -

→ 0 = u - 2×10

→ u = 2 × 10

➡ u = 20 m/s ( initial velocity ) .


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