What was the speed of the projectile when it left the cannon?

In summary, the conversation is about a projectile being shot from the surface of Earth and reaching a height of 35,000 m. The question is to determine the initial speed of the projectile from a given list of options. The equation used to solve this problem is v= square root of GM/r, with M representing the mass of the Earth. The correct answer is option B. The conversation also mentions using conservation of energy to solve the problem.
  • #1
msattar07
10
0

Homework Statement



A projectile is shot from the surface of te Earth by means of a very powerful cannon. If the projectile reaches a height of 35,000 m above Earth's surface, what was the speed of the projectile when it left the cannon?

a. 355 m/s
b. 827 m/s
c. 710 m/s
d. 906 m/s

Homework Equations



v= square root of GM/r

The Attempt at a Solution



theres no mass, so i wasnt sure how to solve it exactly
 
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  • #2
What does capital M denote?
 
  • #3
mass of the Earth
 
  • #4
Well, that's not an unknown mass.
 
  • #5
yea so i plugged it in but didnt get the right answer.

the answer is suppose to be B.
 
  • #6
Well, use conservation of energy:

[tex]U_0 + K_0 = U_f + K_f[/tex]

You know that [tex]U = -\frac{GmM}{r}[/tex]
 

1. What is the definition of projectile speed?

The projectile speed, also known as initial velocity, is the speed at which an object is launched or thrown from a starting point.

2. How is the speed of a projectile calculated?

The speed of a projectile can be calculated using the formula v = √(2gh), where v is the speed, g is the acceleration due to gravity, and h is the height of the starting point.

3. Does the mass of the projectile affect its speed?

No, the mass of the projectile does not affect its speed. As long as the launch force remains constant, the speed of a projectile will be the same regardless of its mass.

4. What factors can affect the speed of a projectile?

The speed of a projectile can be affected by factors such as air resistance, launch angle, and launch force. These factors can either increase or decrease the speed of the projectile.

5. Can the speed of a projectile be greater than the speed of light?

No, according to the theory of relativity, the speed of light is the maximum speed at which anything can travel. Therefore, the speed of a projectile cannot exceed the speed of light.

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