# Search results

1. ### Kinematics-Review help

Ohhhhhh nvm! i just realized what you meant! 20/9.8= 2.0kg f=ma 10=2a therefore a= 5m/s^2 Thanks :D
2. ### Kinematics-Review help

Yea i just realized that thanks..so it would be 15+(-5) = 10 N But weight isn't only the mass, from what i know weight is equivalent to net force that's why it's measured in Newtons..that's where I'm getting confused! oh btw the answer at the back of the textbook says d) 5m/s^2
3. ### Kinematics-Review help

Hey guys, I reallly don't understand how to do this question. i'd really appreciate it if you can help me..thanks :) Homework Statement A person applies a force of 15 N [E] on an object of weight 20 N. If the force of friction has a magnitude of 5.0 N, what is the acceleration of the...
4. ### Optics - distance between object and image

sorry for the late reply but, thanks a lot for your help, I really appreciated it! :)
5. ### Optics - distance between object and image

so the equation is : 1/di +1/do =1/f 1/4do + 1/do = 1/20 Now I'm guessing we want to make do single... but i have to get rid of the 4 so since I'm dividing... 1/do^2 = 1/20 - 1/4
6. ### Optics - distance between object and image

umm.. di=4(do) but since we don't have do we can't solve for di
7. ### Optics - distance between object and image

Yes, I was thinking about that but how do I do it? Seeing as if i did m=di/do 4=di/do --but it leads me to a dead end or if i used 1/di+1/do=1/f i can only go as far as 1/di+1/do=1/20 then once again i get to a dead end!
8. ### Optics - distance between object and image

hello, Homework Statement A lens has a focal length of 20 cm and a magnification of 4. How far apart are the object and the image? Homework Equations m=di(image)/do(object) 1/di + 1/do = 1/f The Attempt at a Solution Well, I don't really know what to do, I feel like I don't have enough...
9. ### Newton's Law Problems

No i don't! But the modified version you gave me is right! I got 1.03! :) thank you soo much :cool:
10. ### Newton's Law Problems

so basically i would multiply mass with 9.81 m2 = 1(9.81) = 9.81 m1= 2(9.81) = 19.62 a= -19.62-(-9.81)sin20/3 a= 3.3m/s^2 (down) but the answer is supposed to be -1.03 m/s^2 (down)
11. ### Newton's Law Problems

Homework Statement A block of mass m1=2.0 kg on a frictionless inclined plane of angle 20 degrees is connected by a rope over a pulley to another block of mass m2=1.0kg. What are the magnitude and direction of the acceleration of the second block? Homework Equations...
12. ### Kinematics Problems

:frown:?

teheh, all the multiples of 9 are the same gifts
14. ### Kinematics Problems

so i basically cross-multiplied and got 35(x+50) = 40x which then gave me 35x + 1750 = 40x 1750= 40x-35x 1750=5x 350=x sub x=350 into x/35 350/35 = 10s That doesn't make sense because the final time is supposed to be 5:40 (basically 40 minutes to add onto 5:00)
15. ### Kinematics Problems

okay when i equated it i got 40t=x+50 and 35t=x now what do i do with the equations?
16. ### Kinematics Problems

sorry i made an error the question is at what time will you pass ms.jones on the highway? Does it change anything?
17. ### Kinematics Problems

Hello! I have another question ..sorry! Problem Mr. Jones lives 50 km away from you. You both leave home at 5:00 and drive toward the highway. Mr.Jones travels at 35km/h and you drive at 40km/h. At what time will you pass Mr.Jones? From the book the answer says: 5:40 This is what...
18. ### Kinematics Problems

^oh, thank you! :D
19. ### Kinematics Problems

^ Why did you make "d" negative? I also don't understand why you have two formulas :( and what I'm doing in each and what I'm trying to find in each!
20. ### Kinematics Problems

Homework Statement An object is dropped from a tower. If it had been thrown down at 60m/s, it would have taken half the time. What is the height of the tower? (acceleration is 10m/s^ down) Homework Equations d= v1(t)+1/2a(t)^ ----> I think you could use this a=v2-v1/t --> maybe...
21. ### Vector Problems

thank you! :) And to everyone else that helped! :)
22. ### Vector Problems

thanks, but i still don't understand what the question is asking me? What does it mean by "ground speed?"
23. ### Vector Problems

okay thanks. One more question.. well actually 2.. if someone knows how to solve problem 2 i would really appreciate knowing how! Average velocity is taken care of now but average speed you you subtract d2-d1 or add d1+d2? Same would go for time...
24. ### Vector Problems

By total displacement do you mean resultant displacement?
25. ### Vector Problems

Oh thanks, that makes more sense. So in the case of problem 1, I would take the resultant displacement- 6500m/ 92s (27 + 65) = 70.7 m/s [SW]
26. ### Vector Problems

So the average speed is going to be 2750 + 5810/ 27+ 65 which is 93m/s ?? The average velocity would be -2750 + (-5810) / 27+ 65 which is 93m/s (SW) Is it right that i added the signs for the velocity?
27. ### Vector Problems

But I thought that was for speed? I'm super confused! aghh... so what would be the answer now?

29. ### Vector Problems

Homework Statement A plane flies 2750 m[W] in 25s and then 5810m [S] in 67s a) What is the average speed of the plane? b) What is the average velocity of the plane? I tried doing it and I don't know if I'm right. My physics teacher can't explain anything for beans so could you please explain...