Investigation Homework

  • Thread starter eassam
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  • #1
eassam
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I was given this and i need help please!

Question 1:
A person has a trip to of 144km to make.
How long will the trip take at a speed of 144 km/h?
How long will it take a speed of 2km/h?
Construct a table showing the time taken (in hours) to complete the journey at 8 different speeds.
Draw a graph of speed versus time-with speed on the horizontal axis and the time on the vertical axis.
What is the rule connecting speed and time?

Question 2:
On a hot day a deer is standing in a narrow railroad tunnel, 80 metres from the west end of the tunnel.
The deer sees a train approaching the tunnel from the west. the train is traveling at a constant speed - a speed that is 10 times as fast as the deer can run.
The deer thinking quickly, realizes that if she runs towards the train she will emerge from the tunnel when the train is 20 metres from the tunnel. However if she runs away from the train, she will be hit just as she reaches the end of the tunnel.
How long is the tunnel?

Question 3:
Kym was about to get her maths test results. She was excited because her mother Irene had promised to give her 70 cents for every question she got right and Kym had to give back 30 cents for every question she got wrong. Kym came home all excited nad said to her mum "mum you owe me $12.00".

How many possible questions were in the test?
You should come out with atleast three answers.

These are the questions can any1 help, if u give the answer please try to give the working out as well. :blushing:
 

Answers and Replies

  • #2
honestrosewater
Gold Member
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eassam said:
I was given this and i need help please!
Post your work. How far have you gotten, and where are you having trouble?
Question 1:
A person has a trip to of 144km to make.
How long will the trip take at a speed of 144 km/h?
How long will it take a speed of 2km/h?
Can you answer these two?

You need to figure out the relationship between speed and time before you can answer Question 2.

Question 3: Can you find the two equations you need to solve this?
 
  • #3
eassam
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i haven't started yet! i need help badly!
 
  • #4
honestrosewater
Gold Member
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Well, people will help you, but we aren't allowed to do your homework for you.
How many hours do you think it will take to travel 144km at a speed of 144km per 1 hour? After 1 hour, how far will you have travelled?
How many hours do you think it will take to travel 144km at a speed of 2km per 1 hour? After 1 hour, how far will you have travelled?
 
  • #5
eassam
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and i thought u wud give me answers!
 
  • #6
honestrosewater
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Here are the rules for homework help: https://www.physicsforums.com/showthread.php?t=28. If you decide to put in some effort, people here can help you through the problems.
 
  • #7
HallsofIvy
Science Advisor
Homework Helper
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eassam said:
and i thought u wud give me answers!

Well, you were wrong- we don't dislike you so much we would sabotage your education! If you cannot do questions like this- that depend on a fundamental understanding of what something like "kilometers per hour" means then your teacher needs to know that in order to help you. Don't try to trick your teacher into thinking you know things you don't!
 
  • #8
eassam
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i can do these questions mate but i need help in how to do working out and then do the answers!
 
  • #9
eassam
10
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can sum1 provide sum equations?
 
  • #10
eassam
10
0
q1: How long will the trip take at a speed of 144 km/h? 1 hour
How long will it take a speed of 2km/h? 72 hours

is this right?
 
  • #11
eassam
10
0
i think q2 is 200 m
 
  • #12
eassam
10
0
q3 i have no clue what to do?
for q1 Draw a graph of speed versus time-with speed on the horizontal axis and the time on the vertical axis how do i do this? also What is the rule connecting speed and time? how do i find this?
 
  • #13
inha
576
1
eassam said:
q1: How long will the trip take at a speed of 144 km/h? 1 hour
How long will it take a speed of 2km/h? 72 hours

is this right?

Yes.

eassam said:
i think q2 is 200 m

How did you get the answer?

eassam said:
q3 i have no clue what to do?
for q1 Draw a graph of speed versus time-with speed on the horizontal axis and the time on the vertical axis how do i do this? also What is the rule connecting speed and time? how do i find this?

You need to find the the amounts of questions answered wrong and right. The situation is constarained by the money condition. Can you form an equation that illustrates the situation based on this?

Speed and time are related to each other by acceleration which tells you how the speed changes as time passes. In general the relation is v(t)=v_0+at where v_0 is the initial speed, a the acceleration and t the time. Think about how the speed changes with time in your assignment. What kind of curves do you think speed vs time should form?
 
  • #14
nomorevishnu
34
0
first two questions are pretty easy...

they can be done by just looking at them and thinking...well the third question can be done easily by some trial and error method...but it doesn't give us two equations that could solve 2 unknowns...1 equation is...X*70-Y*30=1200...can u frame one more eqaution?
 
  • #15
eassam
10
0
thanks for the help guys can u be more specific please?

inha what do u get for q2? i got it by 20*10=200
what can i do instead?

nomorevishnu what wud u get for q2?
is the equation tested?
 
  • #16
honestrosewater
Gold Member
2,136
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For Question 2, first try to figure out where the train is. Draw a line and label points the train, west end of tunnel, deer, and east end of tunnel, in that order. The distance from the deer to the west end of the tunnel is 80m- label it. When the deer reaches the west end of the tunnel, it will have traveled 80m. How far will the train have traveled in this time (speed of train = 10 times speed of deer)?
 
  • #17
eassam
10
0
don't worry guys i ahve figured every thing out by myself thanks for the help provided!
 

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