A railway-line testing-team checking a continuous rail of length 250 m. One tester strikes one end of the rail with a hammer. The other tester hears the sound transmitted through the air and transmitted through the rail. He hears the two sounds at different times. [The speed of sound in steel is 5000 m/s and in air is 330m/s.] b) As the sound wave passes from the end of the beam steel into air.
State the effect of that on

i) the speed of the sound. ………………………………………………………………..

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Acar moves at 12m/s and coasts up a hill with a uniform acceleration of -1.6m/s2. how far has it traveled after 6.0s?

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?