I’m not a science-y person, but I love sci-fi. In a novel I read near a decade ago (Larry Niven’s Known Space series), he mentions occasionally kinetic weapons. I’ve seen this online as well with tungsten-based projectiles being discussed. So my question is how does mass and velocity affect the amount of damage? If I had a nickel-sized object, how fast would it need to go to cause city-wide devastation (would it be possible or would the damage output be capped based on either size or velocity)? Conversely, If I launched something at the speed of sound, would the damage output be the same if it were different-sized objects?
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Some things to consider: there’s resistance in the air, so the object has to be hard enough to not be immediately destroyed on drag. A heavier object requires more energy to travel at the same speed as a smaller object, so higher mass at same speed = higher energy = higher force on impact. (A car vs a marble at 300,000 mph for example, or why a bus at 50 mph wins vs a car 50 mph in collision). As for force required to cause damage, a satellite can get entirely destroyed by a screw from another satellite. So, I’d imagine anything hard enough to withstand air resistance + large enough to not pass directly through the planet + high enough speed, will = force required to = (devastating asteroid). There is no ‘cap’ on nature’s destruction, or creation.
The amount of *energy carried by a moving object* is equal to (mv^2)/2. (m is mass, v is velocity) 2x mass is 2x energy, 2x velocity is 4x energy.
The *force created on impact* is mv/t. (t is time during which the impact occurs and velocity is being changed) 2x mass is 2x force, 2x velocity is 2x force, 2x time is 0.5x force.
There was a video made by Veritasium on youtube, and he explains the kinetic projectile idea quite well.
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