# Search results

1. ### Telescope focal length homework

Hey there.. we havent quite learned anything about the formula you told me about where di = f. the hi/di. Isn't there any other way i can possibly do it?
2. ### Telescope focal length homework

Hey guys, Im really stuck on my homework review and really require help! Someone please help ! :( Homework Statement Question 1: A telescope has a focal length of 18m. If the suns diameter is about 1.39 x 10^9m and its distance from Earth is 1.49 x 10^11, how large is the telescopes image of...
3. ### Hard Kinematics Question-

Thanks Doc Al.. i checked with my physics teacher and that is what he said! :). And for #2.. i added all distances (crosswalk + car + distance travelled by car) and divided them by v1 (speeds at which cars usually travel). Would that measure how long a yellow light will be on? And I cant get...
4. ### Hard Kinematics Question-

I actually got 30m for the first question. I dont understand the 2nd question. For the first one, I found time by v2-v1/ a= t. I added 1s to the answer due to reaction time. V2 is 0.. v1 is 13.9m/s (50 km/h). I then substituted my findings into the equation d= v1 t + 1/2 a t ^2. Which led me to...
5. ### Hard Kinematics Question-

Errr... i got 25m for the first one. by the looks of it, it seems wrong. Anyone else wana help? :(
6. ### Hard Kinematics Question-

Hard Kinematics Question- Please Help! Homework Statement When placing traffic lights at an intersections, planners have to determine how long the yellow light should stay on. This will depend on the speed limit on the road and on the length of the intersection. Outside a building,on the...