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  1. mcT=E 200(370) 500(4200) =74000 2100000 =2174000J =2.174x10^6 2008-11-09 12:20:33 補充: 200(370)+500(4200) =74000+2100000 =2174000J =2.174x10^6 我打少左d + ^^"

  2. Energy gained by water = 5 x 4200 x ( 31.7 - 27 ) = 98700 J That is energy lost of the block is 98700 J change in temperature of the block is 100-31.7=68.3 As heat gain of water = heat lost of the block So, 98700 = heat capacity of the metal block x 68.3 heat...

  3. ...spring) would move along with the force when it is pulled. When one end of the spring is fixed on a wall, the force F that keeps the spring stationary is actually given by the wall.

  4. ...2 , say , frequency = 300 Hz if frequency is decreased to one -third then final frequency = 300 x 1/3 = 100Hz (decreased to...

  5. First of all, please look at the following ray diagram first . http://i718.photobucket.com/albums/ww188/physicsworld2009...it lens R So, the focal length of R, f ' = 1 cm Object distance from R, u = -(3...

  6. ...the angle measured is larger (nearly double) than that of the first order, the % of reading error is smaller. Disadvantage...

  7. ... = 20m = 20(0.005) = 0.1 kg Since in one second, there are 20 pellets ..., by impulse = change of momentum Ft = mv - mu F = (m/t)(v - u) F = (0.1)(0 - 10) F = -...

  8. First of all, F =ma= (mv-mu)/t, where m is mass of the object; v is final velocity; u...

  9. At t= t ,the velocity of the first ball is v the velocity of the secendy ball is 0 (a=v/t therefore...

  10. No. The other one will have the same brightness as before. In a parallel circuit, each bulb is...