Initial Velocity of a Projectile

In summary, the conversation discusses an experiment where rockets were launched and timed to find their initial velocity. The times recorded for each trial are given, and the question asks for the initial velocity without knowing the final velocity. The suggested equation is v = at, with acceleration of 10m/s due to gravity. The discussion also mentions the possibility of disregarding air resistance and using two different rockets for the experiment.
  • #1
sweetcomedygirl
3
0

Homework Statement


"What is the initial velocity of a projectile"
We did an experiment where we launched rockets and timed them from the time they were launched, to the time they hit the ground. Our "Problem" on the lab is to find the initial velocity.

Here are the times we recorded with the first rocket:
Trial 1: 4.38s and 4.5s
Trial 2: 3.625s and the second stopwatch malfunctioned
Trial 3: 3.69s and 3.82s
Trial 4: 3.97s and 3.28s
Trial 5: 3.81s and 3.81s
Here are the times recoded with the second rocket:
Trial 1: 5.35s and 5.31s
Trial 2: 5.62s and 4.6s
Trial 3: 5.18s and 4.6s
Trial 4: 5.53s and 3.68s


Homework Equations


I was thinking, to get velocity in general I could use v = at since we know the times and acceleration = 10m/s due to gravity. But the question asks for Initial velocity, and we don't know the final velocity, so therefore our other equations wouldn't work


The Attempt at a Solution


v = (10)(change in times)
*also, if for example, trial number 1 where i subtract 4.38-4.5 to get the change in time, would I write a negative time or just subtract 4.5-4.38?
 
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  • #2
What do the two times represent? Is it launch to apogee, apogee to landing?

There is a burn period in which the rocket accelerates, follow by slowing down with gravity and air resistance. After apogee, the rocket is in free-fall with gravity, but also with air resistance.
 
  • #3
for this lab I believe we were to disreguarding air restance, and to calculate the initial velocity with only the times and acceleration. We used air-powered rockets, and the two rockets actually represent different washers that we used to control the amount of air-buildup before the rocket was launched. The two times represent two different people timing the same rocket launch with different stopwatches. I hope that helps answer the questions!
 

What is initial velocity of a projectile?

The initial velocity of a projectile is the speed at which the projectile is launched or thrown. It is the velocity at the moment of release or launch.

How is initial velocity of a projectile calculated?

The initial velocity of a projectile can be calculated using the equation V0 = √(g * H), where V0 is the initial velocity, g is the acceleration due to gravity, and H is the height from which the projectile is launched.

What factors affect the initial velocity of a projectile?

The initial velocity of a projectile can be affected by several factors, including the angle of launch, air resistance, and the force applied to launch the projectile.

Why is initial velocity of a projectile important?

The initial velocity of a projectile is important because it determines the trajectory of the projectile and how far it will travel. It also affects the impact force of the projectile upon reaching its target.

How can initial velocity of a projectile be measured?

The initial velocity of a projectile can be measured using a variety of methods, such as using a stopwatch to measure the time it takes for the projectile to travel a known distance, or using motion sensors to track the projectile's movement.

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