An automobile engineer found that the impact of a truck colliding at 14 km/h with a concrete pillar caused the bumper to indent only 6.2 cm. The truck stopped. Determine the acceleration of the truck during the collision.

Question

Bruno Bonilla

Physics

5 July, 16:20

An automobile engineer found that the impact of a truck colliding at 14 km/h with a concrete pillar caused the bumper to indent only 6.2 cm. The truck stopped. Determine the acceleration of the truck during the collision.

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Rachel Flowers · Answer 1

Hello

Here we must use the equation of motion

v^2 = u^2 + 2as; where v is final velocity, u is initial velocity, a is the acceleratoin and is the distance travelled.

We select this one because the time of collision is unknown to us.

We know the truck stopped so its final velocity is 0; thus v = 0.

Converting the initial velocity to SI units, we get 3.89 m/s.

The distance traveled, s, is 0.062 meters.

Inserting all of these values into the equation,

0 = (3.89) ^2 + 2 (a) (0.062)

and solving for a, we get a to be

-122.0 ms^ (-2)

The negative sign indicates the acceleration is in the opposite direction to the initial motion, which means the truck decelerated. This is consistent with the given condition.