1. Lenses with eyes

someone please help. this homework is due tonight and i dont know where to go from here
2. Lenses with eyes

alright so the 1.78 cm needs to be changed to .0178 m. do i need to incorporate that equation somehow or is this a really simple problem?
3. Lenses with eyes

The focal length of a relaxed human eye is approximately 1.78 cm. When we focus our eyes on a close-up object, we can change the refractive power of the eye by about 16 diopters. Calculate the focal length of the eye when we focus closely. 1/di+1/do=1/f im not really sure what to...
4. Lens optics

A typical red blood cell subtends an angle of only 1.90E-5 rad when viewed at a person's near-point distance of 25.0 cm. Suppose a red blood cell is examined with a compound microscope in which the objective and eyepiece are separated by a distance of 12.5 cm. Given that the focal length of the...
5. Camera Lens Problem

The actual frame size of "35-mm" film is 24 mm x 36 mm. You want to take a photograph of your friend, who is 1.70 m tall. Your camera has a 60.0 mm focal length lens. How far from the camera should your friend stand in order to produce a 36.0 mm-tall image on the film? i thought you would...
6. Combination Lens problem

A converging lens of focal length 7.94 cm is 19.7 cm to the left of a diverging lens of focal -6.04 cm. A coin is placed 12.2 cm to the left of the converging lens. A) Calculate the location of the coins final image. B)Calculate the magnification of the coin's final imag. The equation i...
7. Finding magnitude of gravitational force?

im still confused. when i find the distance what do i use as the second mass in the equation. and when i find F for all three spheres how do i find the gravitational force for the sphere at the origin?
8. Finding magnitude of gravitational force?

alright well if i find r then what do i do next?
9. Finding magnitude of gravitational force?

The masses and coordinates of three spheres are as follows: 16 kg, x = 0.75 m, y = 3.00 m; 34 kg, x = -2.50 m, y = -2.75 m; 60 kg, x = 0.00 m, y= -0.75 m. What is the magnitude of the gravitational force on a 30 kg sphere located at the origin due to the other spheres? Homework Equations i...
10. Maximum height of an object

Alright so i set up the second equation like this 0=93.4^2 + 2(-9.8)d and for d i got 445.08 m
11. Rearranging acceleration equations

V = Vo + at X - Xo = Vot + .5at2 v2 = vo2 + 2a(X - Xo) X - Xo = .5(Vo + V)t
12. Rearranging acceleration equations

Starting from the constant-acceleration kinematic equations, write a formula that gives t in terms of xi, xf, vi, and vf. do i solve for acceleration in a equation and then plug it in? Starting from the constant-acceleration kinematic equations, write a formula that gives vf in terms...
13. Maximum height of an object

sorry, but would it turn into a free fall question and the acceleration be -9.8? i tried it and it was wrong..
14. Maximum height of an object

alright well i found the velocity final at 131 m to be 93.40 meters, so would i use the same equation and use that as my velocity initial and my velocity final be 0?