Could a projectile shooting downward at near c lift 300lbs?

In summary, if a 1 pound projectile is shot downward near the speed of light from a stationary, non-fixed object on Earth, it could lift a 300 pound object very far due to its large momentum. The 300 pound object would also escape Earth's gravitational field and continue to travel at a constant speed, potentially even leaving the solar system. The calculations for this scenario also take into account the effects of relativity.
  • #1
falafel1995
3
0
If a 1 pound projectile was shot out of a stationary, non-fixed object (downward) near the speed of light (on earth) would it lift the object if it were 300 pounds? If so, how far?
My friend and I were arguing a hypothetical similar to this.
 
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  • #2
Very far because the momentum of a projectile "near c" is exceedingly large.
 
  • #3
How far would you like it lifted, sailor?

As you've stated it, and as Curl says, I could land the 300lb object on your favorite neutron star with enough force left over to turn it into a black hole.
 
  • #4
Of course. The initial speed of the 300-pound object will be 1/300th the speed of the 1-pound object. There's nothing magical about a large size difference.
 
  • #5
falafel1995 said:
If so, how far?

All the way! More seriously the escape velocity for Earth is ~11kmps, your 300 pound object would be traveling at a speed far greater than this so would shoot straight out of the atmosphere (friction with the atmosphere would cause serious damage but never mind that for now) and straight out of the solar system
 
  • #6
How fast would this object go, assuming no friction?
 
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  • #7
falafel1995 said:
How fast would this object go, assuming no friction?
PS: I don't think 1/300 the speed of light is not fast enough to escape the solar system with respect to the milky way's gravity, ~525 km/s vs ~302 km/s.

Erm, 1/300th of the speed of light is 1,000km/s. Did you misquote your figures or the calculation?
 
  • #8
ryan_m_b said:
Erm, 1/300th of the speed of light is 1,000km/s. Did you misquote your figures or the calculation?

I reworked it. It was calculations.
 
  • #9
You guys didn't consider Relativity. The initial speed of the 300lb object would be much greater than 1/300th that of the 1lb object.
 
  • #10
How far would it go?

It will leave Earth's gravitational field with a fair amount of velocity - whether or not you're taking relativity into account. Of course that's assuming the object is small, I'm not sure how much drag one could get at very large sizes.

Anyway, once it's left the gravitational field, it will keep moving at an almost constant speed (Newton Law #1) - neglecting influences from other bodies. So, as long as it has a clear path, a very long way away indeed.
 

FAQ: Could a projectile shooting downward at near c lift 300lbs?

Can a projectile shot downward at near c lift 300lbs?

The answer is no, a projectile cannot lift 300lbs when shot downward at near c. In order to lift an object, the projectile needs to have a greater force than the weight of the object. Shooting a projectile downward at near c would not provide enough force to overcome the weight of 300lbs.

What is the significance of shooting a projectile at near c?

Shooting a projectile at near c, or the speed of light, is significant because it is the fastest possible speed that anything in the universe can travel. At this speed, the projectile would experience time dilation and length contraction, making it nearly impossible for it to lift a heavy object.

Why is it important to consider the weight of the object when shooting a projectile?

The weight of an object is important to consider because it affects the amount of force needed to lift it. In order for a projectile to lift an object, it needs to have a greater force than the weight of the object. Shooting a projectile downward at near c would not provide enough force to overcome the weight of 300lbs.

Is it possible for a projectile to lift 300lbs at any speed?

Yes, it is possible for a projectile to lift 300lbs at a certain speed. The speed needed to lift an object depends on the weight of the object, the angle at which the projectile is shot, and the force of the projectile. However, it is unlikely that a projectile could lift 300lbs when shot downward at near c.

What factors would affect the ability of a projectile to lift an object?

The ability of a projectile to lift an object is affected by several factors, including the weight of the object, the speed and angle at which the projectile is shot, and the force of the projectile. Other factors such as air resistance, gravity, and external forces can also impact the lifting ability of a projectile.

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