Solving Torque Questions: Mass, Distance & Speed

[Power of One]

Homework Statement

1. Given the mass of Pluto and the sun, and the distance between the two, how would you find how many Earth years are in a Pluto year?

2. A bird flying over you drops a walnut. If the bird is flying horizontal at an altitude of 23.5m, and the walnut travels a horizontal distance of 12.5m, how fast was the bird flying.

Homework Equations

1. Centripetal force= mv^2/r?

2. x= vit +.5at^2?

The Attempt at a Solution

I have no idea where to start. Can someone please help lead me down the right path?

 

[rock.freak667]

1. Given the mass of Pluto and the sun, and the distance between the two, how would you find how many Earth years are in a Pluto year?

The gravitational force between the Sun and Pluto provide the centripetal force needed to keep Pluto in orbit. Use this to get the time it takes Pluto to revolve around the Sun.

2. A bird flying over you drops a walnut. If the bird is flying horizontal at an altitude of 23.5m, and the walnut travels a horizontal distance of 12.5m, how fast was the bird flying.

Yes you need to use 2. x=x₀ v_it -(1/2)gt²

Vertically speaking, what is the initial displacement x₀? What is the horizontal range equal to in terms of time and velocity?

 

[Power of One]

How does the gravitational force used to find the time?

I still don't understand number 2, can someone explain it again?

 

[rock.freak667]

How does the gravitational force used to find the time?

Equate the gravitational force to the centripetal force to find the periodic time T.

I still don't understand number 2, can someone explain it again?

x=x₀+v_it -(1/2)gt²

x₀ is the initial displacement. If the horizontal velocity is v, then what is the range R(=12.5m) equal to?