A train is moving at a speed of 30 meters per second. If the brakes are applied to produce a retardation of 2 meters per second squared, how long will it take for the train to stop?

B. 15 s — Use the first equation of motion to determine the time required for the train to reach a final velocity of zero.

JEE Main · PhysicsEasy

$A train is moving at a speed of u = 30 m/s . If the brakes are applied to produce a retardation of a = - 2 m/s^{2}, how long will it take for the train to stop?$

A. $10 s$
B. $15 s$
C. $20 s$
D. $30 s$

Show correct answer & step-by-step solution

Correct answer: B — $15 s$

Solution

$Identify the given values: initial velocity u = 30 m/s, final velocity v = 0 m/s, and acceleration a = - 2 m/s^{2} .$
$Apply the first equation of motion: v = u + a t .$
$Substitute the known values into the equation: $0 = 30 + (-2)t$.$
$Solve for time: $2t = 30$, which simplifies to t = 15 s .$
$Hence the answer is (B).$

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A train is moving at a speed of u=30 m/s. If the brakes are applied to produce a retardation of a=−2 m/s2, how long will it take for the train to stop?

Solution

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More Kinematics practice questions

$A train is moving at a speed of u = 30 m/s . If the brakes are applied to produce a retardation of a = - 2 m/s^{2}, how long will it take for the train to stop?$