[schneid4323]

Problem 1:
Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. Consider the balls while they are both in flight. You may ignore air resistance. Which statements are true about this situation?
True- Both are in free fall
True - As time progresses, the difference between their accelerations increases
False- As time progresses, the distance between them stays constant
False- As time progresses, the difference between their velocities decreases
True - Ball B will hit the ground after ball A

9.8= acceleration due to gravity if you constantly square that the difference in accellerations will increase the distance will change because they will never be at the same velocity/acceleration the velocity difference will increase because they are at a constant acceleration

Problem 2:
You bring a large cannon along with you on a voyage to a distant planet. You set the cannon on a high cliff and you fire a cannonball horizontally off the cliff into an ocean. The cannonball follows projectile motion until it splashes into the water. Which of the following factors will determine the time that the cannonball is in flight? You should ignore atmospheric ("air") resistance.
yes- height of cliff
Depeneds if the force is conatant probably no im guessing- mass of cannonball
yes- planet's acceleration due to gravity
yes- initial velocity of cannonball
no we are ignoring air risitance- radius of cannonball



Problem 3:
Three forces in the x-y plane act on a 4.50 kg mass: 15.10 N directed at 51o, 9.00 N directed at 142o, and 5.60 N directed at 219o. All angles are measured from the positive x-axis, with positive angles in the Counter-Clockwise direction. Calculate the magnitude of the acceleration.
I got the answer for this: 3.086 m/s^2

Draw the graph, connect the vector and it is your answer, the vector solution solution goes from head to head (Length of the resultant is your magnitude)

Calculate the direction of the resultant force using the same sign convention as above (in degrees).
But how do i do this?

Resolve the vector and that will give you the degree


BTW im a little inebreated but that is how you do it, it may not make any sense though

[ksfrogman]

Y = (gt^2)/2 + (v)t + h

where g = gravity (i.e., -32 ft/sec or -9.8 m/sec)
v = initial velocity
h= initial height
t = time in seconds

Veloicity = 1st derivative of Y = gt + v

[schneid4323]

got the first 2. Still need number 3 and this:

A fire helicopter carries a 561 kg bucket of water at the end of a 24.9 m long cable. Flying back from a fire at a constant speed of 43.6 m/s, the cable makes an angle of 48.4° with respect to the vertical. Determine the force of air resistance on the bucket.

Vectors are your friends. change the weight and speed into force


and this:

A 2016-kg elevator moves with an upward acceleration of 1.86 m/s2. What is the tension in the cable that supports the elevator?

f= m x a equal but opposite force is tension dont forget to get the acceleration of gravity force either you need both

[Josh49]

You all set or need help still?

[Josh49]

I think the key to you getting these problems right is to draw a Free Body Diagram for each of these, with every force and direction. It will really clear things up for you..

And also think about it in a real world sense to check your answers. The elevator for example. If you were holding an elevator by a string, you would need to hold the weight of the elevator to keep it static. Then to accelerate it upwards you would need to exert even more force. So you pulling upwards (or tension) should be the gravitational weight plus the force you are using to accelerate it.

FBD's FTW though. They really help you see the hole picture..

[SoYank]

Originally Posted by ksfrogman

Y = (gt^2)/2 + (v)t + h

where g = gravity (i.e., -32 ft/sec or -9.8 m/sec)
v = initial velocity
h= initial height
t = time in seconds

Veloicity = 1st derivative of Y = gt + v

Calculus and alcohol don't mix. Never drink and derive.

[sixspeed]

My brain isn't up to digesting those questions - but seeing as this post was titled "some more physics..." I guess there's been some previous threads like these. Just wondered if this forum had "suffered" the plane/conveyor belt debate yet?

[Josh49]

Originally Posted by sixspeed

My brain isn't up to digesting those questions - but seeing as this post was titled "some more physics..." I guess there's been some previous threads like these. Just wondered if this forum had "suffered" the plane/conveyor belt debate yet?

It hasn't. Keep it that way..

[just4kickz]

Originally Posted by SoYank

Calculus and alcohol don't mix. Never drink and derive.

good one... haha depends tho... if its easy calculus i can still do it... if its hard... i just end up getting headaches from overthinking

[BMWPower06]

thanks guys, im done with that, ill likely have more questions tonite, seeing as i have more hw. I might end up IMing you smart guys

Anyways thanks for the help again

[Driv3r]

Originally Posted by BMWPower06

Yea this is about the first week of level one college physics. I go to George Washington University in DC. Where are you going?

Not going anywhere yet..But thats a pretty tough school to get into...im sure its going to get MUCH MUCH harder...Good Luck with it..

[BMWPower06]

Originally Posted by Driv3r

Not going anywhere yet..But thats a pretty tough school to get into...im sure its going to get MUCH MUCH harder...Good Luck with it..

actually the semester is almost half over, its summer semester. Then ive got Physics 2 for the second summer semester. Its called physics for non-physics majors so hopefully it wont get too much harder