I need help with a physics problem > General Discussion

Posted: 6/18/2008 1:22:34 PM EDT

Here is a basic problem but I don't have my formulas with me. I know there is somebody here who can help. This is all the information given.

If a projectile is fired at a 45degree angle at 141 m/s what is it's velocity of the projectile when it reaches it's apex?

I know the answer but not how to get there.

Posted: 6/18/2008 1:31:05 PM EDT

[#1]

141 m/s is the resultant. Find the X component vector using law of sign or cosine for right angle triangles. That will be your speed at apex since the y-vector (vertical speed will be zero at that point.)

Assuming this is in a frictionless space.

Posted: 6/18/2008 1:32:27 PM EDT

[#2]

horizontal velocity = constant = muzzle velocity x cos 45

vertical velocity = zero at apex

time to apex = v /a = muzzle vel x sin 45 / 32.174 ft /sec^2

vertical velocity at any time = v0 + 1/2 x a x t^2

Posted: 6/18/2008 1:46:53 PM EDT

[#3]

Thanks. I knew someone here would know.

Posted: 6/18/2008 2:06:36 PM EDT

[#4]

Is this the formula?

Posted: 6/18/2008 2:08:32 PM EDT

[#5]

Quoted:
Here is a basic problem but I don't have my formulas with me. I know there is somebody here who can help. This is all the information given.

If a projectile is fired at a 45degree angle at 141 m/s what is it's velocity of the projectile when it reaches it's apex?

I know the answer but not how to get there.

Need atmospherics, need ballistic coefficient...

Posted: 6/18/2008 2:13:28 PM EDT

[#6]

Quoted:
Thanks. I knew someone here would know.

Be careful asking physics questions in GD...look at the result of a simple airplane problem.

Posted: 6/18/2008 2:20:58 PM EDT

[#7]

Quoted:

Quoted:
Thanks. I knew someone here would know.

Be careful asking physics questions in GD...look at the result of a simple airplane problem.

Yeah, there are some idiots who think that a plane could take off on a conveyor belt! Also, some think that even though there's no oxygen in space, a gun could still fire! What a bunch of idiots!

Posted: 6/18/2008 2:23:48 PM EDT

[#8]

Quoted:

Quoted:
Thanks. I knew someone here would know.

Be careful asking physics questions in GD...look at the result of a simple airplane problem.

Can a .50 caliber 600gr bullet fired at a 45 degree angle and 141 m/s shoot down a fully loaded 737 that's trying to take off from a treadmill running at the same velocity as the plane?

Posted: 6/18/2008 2:25:22 PM EDT

[#9]

Quoted:

Quoted:
Thanks. I knew someone here would know.

Be careful asking physics questions in GD...look at the result of a simple airplane problem.

Yeah, there are some idiots who think that a plane could take off on a conveyor belt! Also, some think that even though there's no oxygen in space, a gun could still fire! What a bunch of idiots!

Doesnt modern gunpowder contain an oxidizer?

Posted: 6/18/2008 2:35:37 PM EDT

[#10]

Quoted:

Quoted:
Thanks. I knew someone here would know.

Be careful asking physics questions in GD...look at the result of a simple airplane problem.

Yeah, there are some idiots who think that a plane could take off on a conveyor belt! Also, some think that even though there's no oxygen in space, a gun could still fire! What a bunch of idiots!

They also think .999bar=1. They probably eat their own feces!

Posted: 6/18/2008 3:15:32 PM EDT

[#11]

There's a thread about cops putting up roadblocks, stopping people from going to their homes in the flood areas.

But that's a roadblock remover if I ever saw one!

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