Astudent standing on a knoll throws a snowball horizontally 4.5 meters above the level ground toward a smokestack 15 meters away. the snowball hits the smokestack 0.65 second after being released. [neglect air resistance.]
approximately how far above the level ground does the snowball hit the smokestack?

2.4 m

Explanation:

Consider the motion along the vertical direction

= initial position of ball above the ground = 4.5 m

= time taken by the ball to hit the smokestack = 0.65 s

= initial velocity of the ball along vertical direction

= acceleration due to gravity = - 9.8 m/s²

= position of ball at the time of hitting the smokestack

Using the kinematics equation

inserting the above values

you would expect a sound wave to speed up. - b)

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia