Quick Projectile Question (1 Viewer)

[nrlwinner]

Hi. I've got a question here. You don't have to answer it, but it would certainly save me some time.

Is it possible to get answers for all these questions.

A lifeboat is dropped from a plane at 100m/s from a height of 1000km (just rounding the numbers off)

a) initial velocity
b) initial horizontal velocity
c) initial vertical velocity
d) range
e) final h-velocity
f) final v-velocity
g) final velocty
h) time taken to fall
i) height from which it was dropped/thrown
j) velocity after 3 seconds
k) height after 3 seconds

I just wrote them all down. If someone could take a look and tell me if its possible to get answers for all of them. It seems that I can't get an answer b because they don'tgive you an angle.

 

[Dx_God]

u can answer all of them, assuming the plane is flying horizontally (which is most of the case). if that's true then the answer to b) is 100m/s

 

[xXmuffin0manXx]

Hi. I've got a question here. You don't have to answer it, but it would certainly save me some time.

Is it possible to get answers for all these questions.

A lifeboat is dropped from a plane at 100m/s from a height of 1000km (just rounding the numbers off)

a) initial velocity
b) initial horizontal velocity
c) initial vertical velocity
d) range
e) final h-velocity
f) final v-velocity
g) final velocty
h) time taken to fall
i) height from which it was dropped/thrown
j) velocity after 3 seconds
k) height after 3 seconds

I just wrote them all down. If someone could take a look and tell me if its possible to get answers for all of them. It seems that I can't get an answer b because they don'tgive you an angle.

lol..not possible because a plane wouldnt be able to fly at an altitude of 1000km....not enough air for the engines to suck in so ill answer the questions assuming that it was 1000m..(1000km is also low earth orbit so a lifeboat would probably disintegrate if a plane could fly)

lols also at the badly expressed question but anyway (assumuing g=9.8)
a) 100m/s
b) 100m/s
c) 0m/s
d) 1428.571429m = 1429m (4 sig figs)
e) 100m/s
f) 140m/s
g) 172.0567052m/s = 172.1m/s (4sig figs)
h) 100/7 seconds
i) 1000m (wtf..?)
j) 129.4m/s
k) 955.9m

im not sure about e) and f) though..

 

[adomad]

lol..not possible because a plane wouldnt be able to fly at an altitude of 1000km....not enough air for the engines to suck in so ill answer the questions assuming that it was 1000m..(1000km is also low earth orbit so a lifeboat would probably disintegrate if a plane could fly)

lols also at the badly expressed question but anyway (assumuing g=9.8)
a) 100m/s
b) 100m/s
c) 0m/s
d) 1428.571429m = 1429m (4 sig figs)
e) 100m/s
f) 140m/s
g) 172.0567052m/s = 172.1m/s (4sig figs)
h) 100/7 seconds
i) 1000m (wtf..?)
j) 129.4m/s
k) 955.9m

im not sure about e) and f) though..

e) is right given that there is no drag. and f) is given by v=u+at which comes out to be 140ms-1 down

 

[xXmuffin0manXx]

e) is right given that there is no drag. and f) is given by v=u+at which comes out to be 140ms-1 down

you said that bit purposely...didnt you ?

okay this is war

 

[nrlwinner]

Can someone help me out on all these questions, well except the obvious ones like a and i. I'm not used to using projectile motion without an angle and time.

 

[Dx_God]

a) 100m/s
b) 100m/s
c) 0m/s
d) 1428.571429m = 1429m (4 sig figs)
e) 100m/s
f) 140m/s
g) 172.0567052m/s = 172.1m/s (4sig figs)
h) 100/7 seconds
i) 1000m (wtf..?)
j) 129.4m/s
k) 955.9m

u forgot to add the directions since he is asking u velocity rather than speed. in an exam u would fail epically though u might have gotten the correct answers (i learnt it the hard way...). and why do u take things so serious? though the truth is that a plane wouldn't get to the height of 1000km (if i recall correctly the world record is around 111km), but it's a theoretical question. if u like to take things so serious then u can't assume gravity to be 9.8ms^-2 due to thickness of crust and basically ur height. then is the air resistance which is not zero but rather =kv^n. then is the tidal force and so on. the result is the question will be too complicated to solve which i'm sure is not what u want to do. u should start to be chill on those kind of things or u will either have a heart attack or u'll fail ur exam because u decided to say no its not possible to questions which require an answer (i've done that in my quiz at my tutoring center and i've scored 0/3 for that question despite the fact that my reason was perfect as said by my tutor)

 

[addikaye03]

Can someone help me out on all these questions, well except the obvious ones like a and i. I'm not used to using projectile motion without an angle and time.

Pretend there is an angle, later set this angle to 0 in your calculations. I've heard of people doing this before.

 

[xXmuffin0manXx]

u forgot to add the directions since he is asking u velocity rather than speed. in an exam u would fail epically though u might have gotten the correct answers (i learnt it the hard way...). and why do u take things so serious? though the truth is that a plane wouldn't get to the height of 1000km (if i recall correctly the world record is around 111km), but it's a theoretical question. if u like to take things so serious then u can't assume gravity to be 9.8ms^-2 due to thickness of crust and basically ur height. then is the air resistance which is not zero but rather =kv^n. then is the tidal force and so on. the result is the question will be too complicated to solve which i'm sure is not what u want to do. u should start to be chill on those kind of things or u will either have a heart attack or u'll fail ur exam because u decided to say no its not possible to questions which require an answer (i've done that in my quiz at my tutoring center and i've scored 0/3 for that question despite the fact that my reason was perfect as said by my tutor)

lol youre the one that just took it seriously there i took it to a level which still allows the plausibility in answering the question..you just took it further to render the question void..sure you cant use 9.8 at a height of 1000km, but it would be safe to use it for 1000m..

you cant realyl take ths question theoretically..at 112km or 1000km..

it's funny that i see you visualising me full agro whilst working out these questions~

but anyway.. i admit that not including the direction would mean i would get some of those questions wrong..

 

[nrlwinner]

lol..not possible because a plane wouldnt be able to fly at an altitude of 1000km....not enough air for the engines to suck in so ill answer the questions assuming that it was 1000m..(1000km is also low earth orbit so a lifeboat would probably disintegrate if a plane could fly)

lols also at the badly expressed question but anyway (assumuing g=9.8)
a) 100m/s
b) 100m/s
c) 0m/s
d) 1428.571429m = 1429m (4 sig figs)
e) 100m/s
f) 140m/s
g) 172.0567052m/s = 172.1m/s (4sig figs)
h) 100/7 seconds
i) 1000m (wtf..?)
j) 129.4m/s
k) 955.9m

im not sure about e) and f) though..

Hi. Thanks for the help. But can you explain how you got d, h and k

 

[xXmuffin0manXx]

d)
,where t>0


t=100/7s






h)
,where t>0


t=100/7s

 

[xXmuffin0manXx]

 

[nrlwinner]

A ball is thrown horizontally from the top of abuilding and lands in a bucket on the ground 50m in fron of the building 3s later.

Is the initial velocity of the projectile 0m/s?

 

[adomad]

o? no, it must have some velocity to land 50m away from where it was thrown...

delta x = ux t .'. 50= 3ux .'. ux = 16.6666666666666666666666666666666666666666666666666666666666666666ms-1

since the question tell you the height of the building or the angle of elevation ( or depression), this answer would suffice IMO. the answer above assumes that the ball was thrown totaly horizontally.

 

[nrlwinner]

o? no, it must have some velocity to land 50m away from where it was thrown...

delta x = ux t .'. 50= 3ux .'. ux = 16.6666666666666666666666666666666666666666666666666666666666666666ms-1

since the question tell you the height of the building or the angle of elevation ( or depression), this answer would suffice IMO. the answer above assumes that the ball was thrown totaly horizontally.

Does this mean there is no initial vertical velocity?

 

[adomad]

yeah, in this case yes,so that would make the total velocity 16.666666667 ms-1.... but there are many other cases that will work.

 

[lordinance]

Its a question in surfing