A0.00545-kg bullet is fired straight up at a falling wooden block that has a mass of 3.08 kg. the bullet has a speed of 720 m/s when it strikes the block. the block originally was dropped from rest from the top of a building and had been falling for a time t when the collision with the bullet occurs. as a result of the collision, the block (with the bullet in it) reverses direction, rises, and comes to a momentary halt at the top of the building. find the time t.

0.06s

Explanation:

We can solve a problem with collision using the principle of conservation of momentum, where

Where v is the velocity after the collision,

Our values are given by,

Replacing we have,

Note= Velocity block is given negative becouse V=-gt before collision, i.e, the direction changes.

For time we can use the equation of gravity, solving for t

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

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y