Calculating Projectile Distance on Pluto

In summary: You can find the distance by finding the time from the vertical displacement.Looks right. You can find the distance by finding the time from the vertical displacement.In summary, an astronaut throws a rock at a speed of 12 m/s and an angle of 25° above horizontal from a height of 3.25 m. The rock travels horizontally before hitting the surface of Pluto, which has a mass of 1.27 E22 kg and a radius of 1.14E6 m. To find the gravitational acceleration on the rock, the formula Fg=(G(m1)(m2))/r2 can be used, where m1 is the mass of the rock and m2 is the mass of Pluto. The mass
  • #1
y90x
47
0

Homework Statement



An astronaut throws a rock at 12 m/s at an angle of 25° above horizontal from a height of 3.25 m above the surface. How far horizontally does the rock travel before hitting the surface of Pluto?

Pluto has a mass of 1.27 E22 kg
And a radius of 1.14E6 m

Homework Equations



(Projectile equations )
d=vo(t) + .5a(t^2)
Dx=vx (t)

The Attempt at a Solution


I know how to solve projectiles , except how do I find gravitational acceleration for Pluto ? [/B]
 
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  • #2
y90x said:
how do I find gravitational acceleration for Pluto ?
Do you know a formula involving the gravitational constant G?
 
  • #3
haruspex said:
Do you know a formula involving the gravitational constant G?

Fg = (Gm)/r^2 ?
 
  • #4
y90x said:
Fg = (Gm)/r^2 ?
Not quite. If you have a force on the left then you need two masses on the right. Or you can have an acceleration on the left and just the attracting mass on the right.
 
  • #5
haruspex said:
Not quite. If you have a force on the left then you need two masses on the right. Or you can have an acceleration on the left and just the attracting mass on the right.

Fg=(G(m1)(m2))/r2
But then , where would the other mass come from ? Only one mass is given
 
  • #6
y90x said:
Fg=(G(m1)(m2))/r2
But then , where would the other mass come from ? Only one mass is given
You only need to know the vertical acceleration of the rock. According to the formula above, the force is proportional to its mass, so the acceleration is independent of its mass.
 
  • #7
haruspex said:
You only need to know the vertical acceleration of the rock. According to the formula above, the force is proportional to its mass, so the acceleration is independent of its mass.

I don’t understand
 
  • #8
y90x said:
I don’t understand
Let the mass of the rock be m. What is the gravitational force on it?
 
  • #9
haruspex said:
Let the mass of the rock be m. What is the gravitational force on it?

That’s what I’m trying to figure out
 
  • #10
y90x said:
That’s what I’m trying to figure out
Use the formula you quoted in post #3. The unknown mass of the rock, m, appears in the answer.
 
  • #11
haruspex said:
Use the formula you quoted in post #3. The unknown mass of the rock, m, appears in the answer.

I’m not trying to find mass, the mass is given .
I’m looking for gravitational acceleration,
I keep getting 0.65 but I’m not sure if that’s correct
 
  • #12
y90x said:
I’m not trying to find mass, the mass is given .
No, the mass you are given is the mass of the planet.
In post #5 you complained that you are not given the mass of the rock, so you cannot use the formula to find the force on it. I keep trying to explain to you that that is not a problem. You can find an expression for the force which includes the mass of the rock as an unknown.
y90x said:
I keep getting 0.65 but I’m not sure if that’s correct
0.65 what? m/s2?
Please post all your working.
 
  • #13
haruspex said:
No, the mass you are given is the mass of the planet.
In post #5 you complained that you are not given the mass of the rock, so you cannot use the formula to find the force on it. I keep trying to explain to you that that is not a problem. You can find an expression for the force which includes the mass of the rock as an unknown.

0.65 what? m/s2?
Please post all your working.

Image1513028246.007019.jpg
 

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  • #14

1. How does the gravity on Pluto affect projectile motion?

The gravity on Pluto is significantly weaker than on Earth, about 1/15th of Earth's gravity. This means that projectiles on Pluto will travel much farther and slower compared to on Earth.

2. What are the factors that affect a projectile's trajectory on Pluto?

The factors that affect a projectile's trajectory on Pluto are the initial velocity, the angle of launch, and the gravitational pull of Pluto. Additionally, air resistance is negligible on Pluto, so it does not play a significant role in the motion of projectiles.

3. How would a projectile behave when launched from the surface of Pluto?

When launched from the surface of Pluto, a projectile will follow a parabolic trajectory due to the gravitational pull of Pluto. However, due to the weak gravity, the projectile will travel much farther and slower compared to on Earth.

4. How would the trajectory of a projectile on Pluto differ from that on Earth?

The trajectory of a projectile on Pluto would differ from that on Earth in many ways. Firstly, the projectile would travel much slower and farther due to the weaker gravity. Additionally, there is no air resistance on Pluto, so the projectile would not experience any drag force. The curvature of the projectile's path would also be less pronounced due to the weaker gravity.

5. Can a projectile achieve escape velocity on Pluto?

Yes, a projectile can achieve escape velocity on Pluto. The escape velocity on Pluto is about 1.2 km/s, which is much lower compared to Earth's escape velocity of 11.2 km/s. This means that a projectile would require less initial velocity to escape the gravitational pull of Pluto.

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