I'm not sure but for the first one, if there were more electrons than protons that would mean the object would have a positive charge so you could put another object that is positively charged near it, to see if it would attract and if it would it would mean it's negatively charged and if it wouldn't it would mean it's positively charged. (not sure)
for the second one, after you've rubbed the balloon oh hair, the electrons from your hair have transferred onto the balloon, meaning that the balloon is now negatively charged. because the wall is neutral, it means that it has the SAME number of both protons and electrons ( positive and negative charges cancel out to create a neutral charge). because the protons are positively charged, and the balloon is negatively charged, the two objects will attract because opposite charges attract. this happens because of static electricity.
hope this helps :)
Answer:
tire marks are due to the increase in thermal energy
Explanation:
When a tire is spinning at a given speed when the brakes are applied hard, the friction between the tire's particulate and the ground surface is high enough that some tire particles are transferred to the ground.
This is reflected in the heat transfer from the tire to the ground.
Consequently, tire marks are due to the increase in thermal energy and the change in the friction force of the tire.
Answer:
Lenses produce images through REFRACTION but mirrors produce images through REFLECTION.
CONVEX lenses and CONCAVE mirrors focus light at a point. CONVEX mirrors and CONCAVE lenses spread light apart.
Explanation:
Refraction guides the image formation for lenses. Light rays are bent or refracted at both surfaces of the lens as they pass through it. With this, various effects can be obtained by focusing light rays on different range of curvatures of the lens.
Reflection guides the formation of images by plane and curved mirrors. Light rays change direction as they travel through a continuously changing medium. The law of reflection states that the angle of reflected ray is equal to the angle of incident ray upon reflection from a smooth surface.
A convex lens is curved outward causing the parallel light rays passing through it to be refracted inward. They meet at a focal point and focuses light at a single point likewise concave mirror.
A concave lens is curved inwards and light rays passing through it are refracted outward, spreading light apart which is also an action of convex mirror.
Answer:
h ’= 12,768 cm
Explanation:
For this exercise let's use the constructor equation
1 / f = 1 / p + 1 / q
where f is the focal length, p the distance to the object and q the distance to the image
the magnification equation is
m = h '/ h = -q / p
let's find the distance to the object
1 / p = 1 / f- 1 / q
1 / p = 1/20 - 1 / (- 37.5)
1 / p = 0.076666
p = 13.04 cm
now let's use the magnification equation
h ’= - q / p h
let's calculate
h ’= - (-37.5) / 13.04 4.44
h ’= 12,768 cm
