Question

A 10 kg rock falls from a height of 18 m and lands on a guy about 3s later. How much power did it hit him with?

Answer 1

Answer:

Velocity after 3 sec. =

$v = u + gt = 0 + 9.8 \times 3 = 29.4 \\ power = m \times v = 10 \times 29.4 = 294 \: w$

Answer 2

Answer: The power can be expressed as 588.8 W = 0.78 horsepower (approx)

Explanation:

here is a step-by-step explanation of how to calculate the power of the rock hitting the guy:

• Start by calculating the weight of the rock.

The weight of an object is equal to its mass multiplied by the acceleration due to gravity ( W = m*g).

• In this case, the mass of the rock is 10 kg and the acceleration due to gravity is 9.8 m/s².
• Therefore, the weight of the rock is 10 kg * 9.8 m/s² = 98 N.

• Next, calculate the amount of work done by the rock.
• Work is equal to force multiplied by distance
• ( work done =force * distance).
• In this case, the force is the weight of the rock (98 N) and the distance is the height from which the rock fell (18m). Therefore, the amount of work done by the rock is 98 N * 18 m = 1764 J.

• Now, divide the amount of work done by the time it took to do that work ( Power = work done / time).
• In this case, the time is 3 seconds. Therefore, the power is equal to 1764 J / 3s = 588.8 W.

To convert it to other units like horsepower, we can use the conversion factor 1 horsepower = 746 W.

Therefore, the power can be expressed as 588.8 W = 0.78 horsepower (approx)

It's important to note that the work done and power can be calculated using the kinetic energy also, which is 1/2 * m * v², where m is the mass and v is the velocity at impact, assuming that rock is falling vertically, the velocity at impact would be (2gh)^1/2.

To learn more about kinetic energy from the link below

https://brainly.in/question/1797886

To learn more about acceleration due to gravity from the link below

https://brainly.in/question/2073284

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