A car's bumper is designed to withstand a 4.32 km/h (1.2 m/s) collision with an immovable object without damage to the body of the car. The bumper cushions the shock by absorbing the force over a distance. Calculate the magnitude of the average force (in N) on a bumper that collapses 0.150 m while bringing a 820 kg car to rest from an initial speed of 1.2 m/s. (Enter a number.)

3936 N

Explanation:

m = Mass of car = 820 kg

u = Initial velocity = 1.2 m/s

v = Final velocity = 0

d = Distance = 0.15 m

The work done is given by the change in the kinetic energy of the system

The magnitude of force is 3936 N

Explanation:

Given:

Now by the law of energy conservation, the work done is the energy compensated in bringing the car to rest.

where:

work done by the force F

change in kinetic energy

measuring things 1 litre of water

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