Answer: f=150cm in water and f=60cm in air.
Explanation: Focal length is a measurement of how strong light is converged or diverged by a system. To find the variable, it can be used the formula:
= (nglass - ni)(
- 
).
nglass is the index of refraction of the glass;
ni is the index of refraction of the medium you want, water in this case;
R1 is the curvature through which light enters the lens;
R2 is the curvature of the surface which it exits the lens;
Substituting and calculating for water (nwater = 1.3):
= (1.5 - 1.3)(
- 
)
= 0.2(
)
f = 
= 150
For air (nair = 1):
= (1.5 - 1)( - )
f = 
= 60
In water, the focal length of the lens is f = 150cm.
In air, f = 60cm.
1. Answer: A skydiver whose air resistance is equal to that of her weight.
A skydiver free falls under gravity but her rate of fall slows down due to drag -air resistance. when this air resistance becomes equal to her weight, the two get balanced and the body does not accelerate or decelerates.
2. Answer: Gravity
Contact forces are those which act when there is physical contact between two bodies. For example: normal force, tension and spring force.
Non-contact forces act between two bodies even when they are at a distance apart. For example: gravity, electric force, magnetic force etc.
3. Answer: The tendency of an object's motion to remain the same.
Inertia is a property of matter by virtue of which it tends to remain in its state of motion or rest. It does depend on mass of the object, more the mass, more is inertia. For example, cycle can be easily moved but we need real push hard for a car to move.
4. Answer: 254 N
The man pushes the box with 310 N force at an angle of 55 degrees to the horizontal.
we can write this in terms of horizontal (
)and vertical component (
).
Horizontal component: 
Vertical component: 
The vertical component would act towards the floor making the job more difficult to move the job.
Sorry, I don't know but I think the correct answer is the first option.
Answer: particles movement in solid< particles movement in liquids< particles movement in gases.
Explanation:
Atoms are very small, it is not easily seen even with the help of light microscopes. However, We use multiple models of atoms toexplain describe particles of an atom behaviour.
In solids, the particles are packed together tightly in an ordered arrangement. The particles only vibrate about their position in the structure because the particles are held together too strongly to allow movement. Thereby,making the particles MOVE THE LEAST
In liquids, the particles are close together and they move with random motion in the container. The particles move rapidly in all directions but there is more colision between itself even more than particles in gases. This means that the particles here are MORE FASTER THAN THAT OF THE SOLID.
Particles in gases move the FASTEST, more than the particles in solids and liquids. Although, the average speed of the particles depends on their mass and the temperature.
Answer:
The velocity is 
Explanation:
From the question we are told that
The electric field is 
The magnetic field is 
Generally the force experienced by the electron due to the magnetic field is
Generally the force experienced by the electron due to the electric field is
Since from the question the net force is zero then
=> 
Substituting values
