It is used to reduce the friction
Answer:
Explanation:
Impulse = change in momentum
Initial momentum = mass x initial velocity = 100 x 5 = 500 kg m/s
final momentum = mass x final velocity = 100 x - 4 = -400 ( - ve sign due to reversal of direction )
change in momentum = final momentum - initial momentum
= - 400 - 500 = - 900 kg m/s .
As it is - ve , it acts upwards .
So magnitude of impulse on Perter = 900 kg m/s
In physics, gravity is the natural force that causes things to fall toward the earth. The noun gravity can also mean seriousness or solemnity. Someone who conducts themselves with an air of gravity is someone who takes what they are doing seriously.
A magnet is any object that has a magnetic field. It attracts ferrous objects like pieces of iron, steel, nickel and cobalt. In the early days, the Greeks observed that the naturally occurring 'lodestone' attracted iron pieces. From that day onwards began the journey into the discovery of magnets.
These days magnets are made artificially in various shapes and sizes depending on their use. One of the most common magnets - the bar magnet - is a long, rectangular bar of uniform cross-section that attracts pieces of ferrous objects. The magnetic compass needle is also commonly used. The compass needle is a tiny magnet which is free to move horizontally on a pivot. One end of the compass needle points in the North direction and the other end points in the South direction.
The end of a freely pivoted magnet will always point in the North-South direction. The end that points in the North is called the North Pole of the magnet and the end that points South is called the South Pole of the magnet. It has been proven by experiments that like magnetic poles repel each other whereas unlike poles attract each other.
