Answer:
Explanation:
There are two forces acting on the person as he's standing on the scale in the elevator:
- Its weight, , downward, with m = 45.0 kg being his mass and g = 9.8 m/s^2 being the acceleration of gravity
- The normal reaction exerted by the scale on the person, N, upward, which is equal to the value read on the scale, N = 460 N
Using Newton's second law, we can write
Where a is the acceleration of the person (and of the elevator). Solving for a,
And since we chose positive as the upward direction, the acceleration is upward.
The correct answer is the Type of batteries
Explanation:
In an experiment, it is normal the researcher modifies one variable, in this case, the number of batteries (independent variable), and this variable affects the variable tested, in this case, the brightness of the bulb (dependent variable).
However, other factors or variables should be constant to guarantee the results are reliable. In this context, one factor that the student should keep constant is the type of batteries he uses because this is not one of the main variables and therefore it is not expected he changes this on purpose or this is affected by other variables. Moreover, by making any change the experiment can be negatively affected. For example, batteries might differ in their power capacity this can affect the brightness of the bulbs.
Answer:
grid or metal sheets or metal foams
Explanation:
Electric and magnetic fields are generated in electrical circuits that often cause interference in the measurements made.
To avoid these interferences, shields are generally used for the electric fields, Farday boxes are used, which are metal grids connected to earth.
For the magnetic field there is also a grid or metal sheets or metal foams,
It should be noted that the gaps in the screening must be smaller than the wavelength of the radiation to be screened.
Answer:
When the object is placed between centre of curvature and principal focus of a concave mirror the image formed is beyond C as shown in the figure and it is real, inverted and magnified.
Explanation:
Velocity ratio of simple machine is the ratio of distance travelled by effort to the distance travelled by load in the machine. The efficiency of a simple machine is defined as the ratio of useful work done by machine (output work) to the total work put into the machine (input work).
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