Need help with my homework 45minutes left till i have to hand it in

  • Thread starter Thread starter MBEE
  • Start date Start date
  • Tags Tags
    hand Homework
AI Thread Summary
Bianca needs a concave mirror for her solar cooker to focus sunlight on a single point. To calculate the focal length of her mirror made from a 96cm diameter beach ball, use the formula f = R/2, resulting in a focal length of 48cm. A diagram should illustrate the mirror, the sun's rays converging towards the focal point, and the placement of her food. The image produced by the solar cooker is real and inverted. At 5cm from the focus, the effectiveness of the cooker decreases as the food cannot be concentrated at a single point, impacting cooking efficiency.
MBEE
Messages
2
Reaction score
0
[URGENT] Need help with my homework! 45minutes left till i have to hand it in

Homework Statement



a) Bianca wants to make a solar cooker to take on her camping trip
what type of mirror does she need?

b) Bianca makes a mirror by putting silver foil on an old, cut-up beach ball. The ball has a diameter of 96cm. Calculate the focal length of the mirror.

c) Draw a diagram to show the mirror, the direction of the sun's rays, and the position of bianca's food.

d)State the nature of the image produced by the solar cooker

e) Bianca's food cannot all be at one point. Discuss the effectiveness of the solar cooker at 5cm from the focus.


Homework Equations



1/f=1/do+1/di

m=di/do=hi/ho

siso=f2

m=f/so=si/f

The Attempt at a Solution


 
Physics news on Phys.org


I'm really bad at physics:S
 


MBEE said:

Homework Statement



a) Bianca wants to make a solar cooker to take on her camping trip
what type of mirror does she need?

b) Bianca makes a mirror by putting silver foil on an old, cut-up beach ball. The ball has a diameter of 96cm. Calculate the focal length of the mirror.

c) Draw a diagram to show the mirror, the direction of the sun's rays, and the position of bianca's food.

d)State the nature of the image produced by the solar cooker

e) Bianca's food cannot all be at one point. Discuss the effectiveness of the solar cooker at 5cm from the focus.


Homework Equations



1/f=1/do+1/di

m=di/do=hi/ho

siso=f2

m=f/so=si/f

The Attempt at a Solution



a) You need a mirror that focuses light on 1 point, which mirror does this?

b) f = R/2

c) You can probably do this yourself..., the sun's rays would be horizontal lines toward the mirror

d) Again, once you have the ray diagram, this is self explanatory.

e) This is a magnification problem, so use M=di/do
 


You need to fill out this:
MBEE said:

The Attempt at a Solution

first.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top