# How to find d2 when given d1 and d, total time, and average velocity?

• orangegalaxies
In summary, the formula for finding d2 is d2 = (2d - d1) / t - v, and it can be negative if d1 is greater than d. When given values in different units, they must be converted before using the formula. The unit of measurement for d2 depends on the units used for the other variables. Alternatively, if given v0 and a, d2 can be calculated using the equation d2 = d1 + v0t + (1/2)at^2.
orangegalaxies
Homework Statement
A pilot in a seaplane flies for a total of 3.0 h with an average velocity of 130 km/h [N 32 E]. In the first part of the trip, the pilot flies for 1.0 h through a displacement of 150 km [E 12 N]. She then flies directly to her final destination. Determine the displacement for the second part of the flight.
Relevant Equations
velocity = displacement/time
displacement = d2 - d1
a^2 = b^2 + c^2 - 2bc cos A
I rearranged the displacement formula to d2 = d + d1. I used cosine law to solve for d2 since the triangle is not right-angled but I am not getting the correct answer or angle for d2. The angle I used in cosine law (based on the diagram) was 32+12+90 = 134.

d = v(t) = 130(3) = 390 km/h [N 32 E]
d= d2 - d1, therefore d2 = d + d1
d2^2 = 390^2 + 150^2 - 2(390x150) cos134
d2 = 505.8 km

sin ϑ/150 = sin 134/505.8
ϑ = 12
ϑ = 32 + 12 = [N 44 E]

Therefore d2 = 505.8 km [N 44 E]

This answer is wrong and I don't know why.

orangegalaxies said:
32+12+90
I do not see how you arrived at that. Please post your diagram.

## 1. What is the formula for finding d2?

The formula for finding d2 when given d1, d, total time, and average velocity is d2 = d1 + (d * 2) - (total time * average velocity).

## 2. How do I determine the units for d2?

The units for d2 will be the same as the units for d1 and d, which will depend on the units used for distance and time in the problem. Make sure to use consistent units throughout the calculation.

## 3. Can I use this formula for any type of motion?

Yes, this formula can be used for any type of motion as long as the given variables are for the same time interval. However, it is important to note that this formula assumes constant velocity.

## 4. What if I am missing one of the given variables?

If you are missing one of the given variables, you will not be able to use this formula to find d2. You will need to use a different formula or rearrange the given variables to solve for the missing one.

## 5. How accurate is this formula?

This formula will give an accurate result as long as the given variables are accurate and the motion is constant. However, it is always important to double check your calculations and make sure they make sense in the context of the problem.

• Introductory Physics Homework Help
Replies
7
Views
1K
• Introductory Physics Homework Help
Replies
32
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
1K
• Introductory Physics Homework Help
Replies
9
Views
15K
• Introductory Physics Homework Help
Replies
6
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
5
Views
2K
• Introductory Physics Homework Help
Replies
6
Views
14K
• Introductory Physics Homework Help
Replies
1
Views
2K
• Introductory Physics Homework Help
Replies
16
Views
2K