# Physics

posted by on .

I got a few questions that I need to be checked please?

Why does a brick weigh 1 kilogram. Explain.

-Would it be cause there are not other forces acting on it that's why it weighs 1 kilogram?

Why do lurch foward when a bus slows down? What law is this?

-Is it because the bus is still in motion and you are at rest causing you to lurch foward. It is Newtons first law: the law of intertia

• Physics - ,

yes and yes

• Physics - ,

For the first one, look up weight and the gravitational force of the earth.
For #2, inertia is ok but the reasoning is wrong. The bus is moving a some speed and the passengers in the seats are moving at the same speed (perhaps I should be saying velocity). When the bus slows down to, say, half that speed, the passengers still are going at the original speed so they try to move forward. That's why the lurch is forward. That's why a head on collision is so deadly. The two cards stop within the blink of an eye BUT the two drivers of the two vehicles keep moving--often through the windshield.