[BMWPower06]

Having trouble with a couple of physics problems, here is the first one:

At the National Cannon Testing Facility, a cannonball has been launched with an initial velocity v at a particular angle. As the cannonball is in the air, we refer to the x-component of its velocity as v(x) and the y-component of its velocity as v(y). Which of the following statements are true about the motion of the cannonball?
True False- The time in the air depends only on v(y) and not on v(x)
True False- As the cannonball travels, its v(x) is changing
True False- At the top of its trajectory, v(x) is zero
True False- The maximum height depends only on v(y) and not on v(x)
True False- The y-component of the acceleration is -g



Problem 2:

Which of the following factors are relevant in determining the range of a projectile that is launched on a very large flat plain? (i.e. no hills or cliffs)
yes no- mass of projectile
yes no- initial launch angle
yes no- acceleration due to gravity on Earth
yes no- volume of projectile
yes no- initial launch speed



Problem 3:


Which of the following statements are true about the situations depicted in the figures above?
True False- The tension in the rope is equal in pictures G and H
True False- The tension in the rope in picture G is 40 N
True False- The tension in the rope is zero in pictures A, F and H
True False- The tension in the rope is smaller in picture H than in picture B
True False- The tension in the rope is greater in picture G than in picture E

TIA to any physics genius that can help. :hi:

[zenmaster]

I dunno, I got:
TRUE,TRUE if angle not equal to 90,TRUE,TRUE,TRUE
YES,YES,YES,YES,YES
FALSE,FALSE,FALSE,FALSE,FALSE

[MonacoBimm]

This is an awesome idea. I can have my fellow e90post member/brothers help me out on my homeworks!!!!!!!!!!!!!!!!!!!!

[just4kickz]

At the National Cannon Testing Facility, a cannonball has been launched with an initial velocity v at a particular angle. As the cannonball is in the air, we refer to the x-component of its velocity as v(x) and the y-component of its velocity as v(y). Which of the following statements are true about the motion of the cannonball?
True False- The time in the air depends only on v(y) and not on v(x) T
True False- As the cannonball travels, its v(x) is changing F
True False- At the top of its trajectory, v(x) is zero F
True False- The maximum height depends only on v(y) and not on v(x) T
True False- The y-component of the acceleration is -g T

[just4kickz]

Problem 2:

Which of the following factors are relevant in determining the range of a projectile that is launched on a very large flat plain? (i.e. no hills or cliffs)
yes no- mass of projectile y
yes no- initial launch angle y
yes no- acceleration due to gravity on Earth y
yes no- volume of projectile n
yes no- initial launch speed y

[just4kickz]

#3 i cant remember

[skim7x]

1a. True
1b. True (due to air resistance; if no air resistance, then it's False)
1c. False (v(y) is zero at the top of its trajectory)
1d. True
1e. True

[skim7x]

2a. no (mass would affect the energy it takes to accelerate the object, not on the range... but its a poorly worded question)
2b. yes
2c. yes
2d. no (but if you take air resistance into account, the answer is 'yes' - refer to Galileo's experiment at the leaning tower of pisa)
2e. yes

[skim7x]

aaaand I'm too lazy to think about #3 good luck! haha

[zenmaster]

change 1c to false! heh!

[BMWPower06]

Originally Posted by skim7x

2a. no (mass would affect the energy it takes to accelerate the object, not on the range... but its a poorly worded question)
2b. yes
2c. yes
2d. no (but if you take air resistance into account, the answer is 'yes' - refer to Galileo's experiment at the leaning tower of pisa)
2e. yes

this is correct!!!
You guys are the best

for all of you

Thanks for the help guys!!

[MrFrizzle]

lol, how old are you?
Haha, I had to learn all this stuff in my AP Physics class now too

[just4kickz]

Originally Posted by skim7x

2a. no (mass would affect the energy it takes to accelerate the object, not on the range... but its a poorly worded question)
2b. yes
2c. yes
2d. no (but if you take air resistance into account, the answer is 'yes' - refer to Galileo's experiment at the leaning tower of pisa)
2e. yes

wow totally forgot the concept of the answer to 2a... a rock and a feather will fall at the same rate given a controled environment... hahaa damn i hella remember that... 2a is f

[zenmaster]

2a. no (mass would affect the energy it takes to accelerate the object, not on the range... but its a poorly worded question)

Yeah, it's a poorly worded question. However, answer is YES. Mass would affect range. In other words, a 5lb cannon ball will not go as far as a 10lb cannon ball if they both had the same initial velocity and size.

[zenmaster]

Originally Posted by just4kickz

wow totally forgot the concept of the answer to 2a... a rock and a feather will fall at the same rate given a controled environment... hahaa damn i hella remember that... 2a is f

Wrong!

[BMWPower06]

Originally Posted by MrFrizzle

lol, how old are you?
Haha, I had to learn all this stuff in my AP Physics class now too

18 im taking summer physics over the summer to get it outta the way. You guys are damnnn good at this. I have hw almost everynight. Expect to see more threads

[skim7x]

Originally Posted by zenmaster

Yeah, it's a poorly worded question. However, answer is YES. Mass would affect range. In other words, a 5lb cannon ball will not go as far as a 10lb cannon ball if they both had the same initial velocity and size.

A 5lb cannon ball WOULD go as far as a 10lb cannon ball if they had the same initial velocity and size. The only force acting on each object on the 'x-axis' is air resistance. Both balls, being the same size, would travel the same distance given the same initial velocity (only the 10lb ball would take more energy to reach that velocity than the 5lb ball). Refer to Galileo's experiment at the leaning tower of pisa

Originally Posted by zenmaster

just4kickz: wow totally forgot the concept of the answer to 2a... a rock and a feather will fall at the same rate given a controled environment... hahaa damn i hella remember that... 2a is f

zenmaster: Wrong!

If just4kickz is referring to a "controlled environment" as a vacuum (ie. no air), he is correct--a rock and a feather will fall at the same speed.

[just4kickz]

Originally Posted by skim7x

A 5lb cannon ball WOULD go as far as a 10lb cannon ball if they had the same initial velocity and size. The only force acting on each object on the 'x-axis' is air resistance. Both balls, being the same size, would travel the same distance given the same initial velocity (only the 10lb ball would take more energy to reach that velocity than the 5lb ball). Refer to Galileo's experiment at the leaning tower of pisa

If just4kickz is referring to a "controlled environment" as a vacuum (ie. no air), he is correct--a rock and a feather will fall at the same speed.

yeah... im assuming the question involves controlled environments since its basically multiple guess... haha.... i hate physics but i love thinking about these concepts.

[just4kickz]

+1 to skim's explanation...

given the same conditions, no air resistance (we're all assuming this because this is probably a basic physics class teaching basic concepts) both cannon balls would have the same range.

think of the problem as a vector where the hypotnuse is the intial velocity. from the angle of elevation, the "x" remains constant through time, while the "y" decreases @ an acceleration of -9.8m^2/s

[Neurorad]

Where in VA are you?

[skim7x]

Originally Posted by Neurorad

Where in VA are you?

I think I know where you're going with this... and I'm pretty sure there is air resistance in VA... might have to wikipedia that one, though...

[BMWPower06]

Originally Posted by Neurorad

Where in VA are you?

Northern... why?