Question

an astronaut drops a rock from the top of a crater on the moon when the rock is halfwat down to the bottom of the crater its speed is what fraction of its cinal impact speed?A. 1/4–√2B.1/4C. 1/2–√2D. 1/–√2Answer:

Answer 1

The fraction of its final impact speed is 1/√2.

Impact speed is the speed of the vehicle at the time of impact or collision.

The rock has lost half of its gravitational potential energy, its kinetic energy at the halfway point is half of its kinetic energy at impact.

As we know kinetic energy is directly proportional to mass (m) and velocity square (v²),

KE ∝ v²

KE = (1/2)mv²

then K.E at halfway point is equal to 1/2 x K.E,

Then,

The K.E at impact, then the rock’s speed at the halfway point its speed at impact will be 1/√2 its impact speed.

Therefore option D is the correct answer, the fraction of its final impact speed is 1/√2.

To know more about impact speed,

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