this question doesnt' make sense to me?...help?

Question

I was suppose to do this question...but it doesnt make any sense...

pg 62#3d

3a) A russion MiG-25 flies at 3395km/h. Convert its speed to m/s
b) a sneez takes o.5 s. Find the distnace the plane flies in the time it takes you to complete one sneez.
c) find the planes average acceleration if it takes 12.0 s to reach this speed from rest.
D) from what speed must the plane start in order to reach its final spped in 8.7 s?...<--is there enough info even??!

I know how to do a, b, c, but D is the one i have prblem!!...is there enough info?!?

Answer 1

Okay. Here's what I got.
If the MiG-25 flies at 3395km/h, that means it flies at 943.06m/s (A).
If the sneeze takes 0.5 seconds, then the distance the plane would cover is 471.53m (B).
In order to discover the acceleration of the plane you divide 471.53 by 12.0 giving you 39.29 m/s of acceleration.
This is enough information to complete this problem.
Now the formula for acceleration and speed is as thus:

Acceleration= (final speed - original speed)/total time

What you have then is :
39.29= (943.06-x)/8.7

Multiply by 8.7 to simplify the equation which gives you:
341.823= 943.06-x

Subtract 943.06 to both sides to get x by itself:
(341.823-943.06)=(943.06-x-943.06)
-601.237 = -x

Multiply each side by -1 to make x a positive integer.
What you have is that your plane needs to start out by going 601.237 m/s to reach it's final speed (943.06 m/s) in 8.7 seconds.

Hope it helped you.

Answer 2

The problem you are having is that reality is affecting your judgment. You know that resistance is non-linear and even in space the acceleration would be non-linear.

3a) A russion MiG-25 flies at 3395km/h. Convert its speed to m/s
Multiply by 1000 and drop the metric prefix K, then divide by 60.

b) a sneez takes o.5 s. Find the distnace the plane flies in the time it takes you to complete one sneez.
Multiply 0.5 times what you got in 3a)

The last two are defective but they can be answered. But judging from the simplicity of the first two questions it seems way out of range. As a constant linear velocity.

c) find the planes average acceleration if it takes 12.0 s to reach this speed from rest.

The average velocity of an object undergoing constant acceleration is (vi + vf)/2 , I guess vi is 0 and vf is 3A).

D) from what speed must the plane start in order to reach its final spped in 8.7 s?...<--is there enough info even??!

Answer 3

a) multiply by 1000 and divide by 3600 to convert to m/s
b) multiply the value from part a by .5 s to find a distance in meters
c) take the final velocity (answer in part a) subtract initial velocity (zero m/s since the plane starts still) and divide by 12 seconds. the answer will be in the unit meters per seconds squared.
d)Multiply the answer from part c by 8.7 seconds to get a value in m/s. Then add the final velocity which is the answer from part a. The answer will be in m/s.

Equations you should learn (Vf-Vi)/t=a Vt=d

Answer 4

a,convert its speed by using formula:
3395 x 1000 / 60 x 60=1109.722 m/s

b,it travels 1109.722 in 1 second
therefore 0.5s = 1109.722 / 2 = 554.861

i am sorry but i don't know c and d

Answer 5

a) 3395 km/h = 3395 /60 / 60 km/s x 1000m/km = 943 m/s
b) d = v x t = 943 m/s x 0.5 s = 471.5 m
c) v = v0 + at, where v0 = 0 ("from rest")
943 m/s = a x 12s
a = 943/12 m/s2
a = 78.6 m/s2
d) v = v0 + at , where final v is 943 m/s and t = 8.7s
find v0
943 m/s = v0 + 78.6 m/s2 x 8.7s
943 m/s = v0 + 683.7 m/s
v0 = (943 - 683.7) m/s = 259.3 m/s

Answer 6

What is this 3rd grade physics. Buddy if you don't understand these questions then obviously you haven't even cracked open the book. Read the book! How many seconds are there in an hour? How many meters in a kilometer?

D = 260m/s

Answer 7

Answers

a) 943.05 m/s
b) 471.52 m
c) 282.91 km/s
d) 933.63 km/s

all the information is there work it out

Answer 8

prior to starting both planes are standing still

Answer 9

I think that you should ask someone you know for help.
i can do it but it is kinda hard to describe in words.
Maybe if i wasn't a freshman in highschool i might be able to describe it in words.
Once you see how to do it, it's really easy.

Answer 10

ummmmm hmmmmm ummmmmmm i have no idea.