A fast train approaches a car waiting at a grade crossing and sounds its horn. A person in the car will notice that, compared to what it would be if the train were at rest, the horn sound's
A. frequency appears to be lower.
B. wavelength appears to be longer.
C. wavelength appears to be the same.
D. frequency appears to be higher.
Answer: D
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Two metal rods, one silver and the other copper, are both immersed at one end in a steam chamber at a temperature of 100°C. The other end of each one is in an ice water bath at 0°C
The rods are 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and the surroundings, except at the ends. How much total heat flows through the two rods each minute? The thermal conductivity of silver is 417 W/m ? K, and that of copper is 395 W/m ? K. A) 20 kJ B) 39 kJ C) 47 kJ D) 49 kJ E) 11 kJ
A 2.0-kg block slides on a rough horizontal surface. A force (magnitude P = 4.0 N) acting parallel to the surface is applied to the block. The magnitude of the block's acceleration is 1.2 m/s2 . If P is increased to 5.0 N, determine the magnitude of the block's acceleration
a. 2.1 m/s2 b. 2.3 m/s2 c. 1.9 m/s2 d. 1.7 m/s2 e. 3.2 m/s2
A heavy man and a light man parachute together from a high-flying plane. The first to attain zero acceleration will be the
1) light man 2) heavy man 3) both will attain zero acceleration at the same time. because 4) the gravitational force on each man is the same. 5) of the lesser gravitational force acting on the lighter man. 6) air resistance will eventually counterbalance the weights of both men. 7) the lighter man will not have to fall for as long a time before air resistance equals his weight.
A boy with a mass of 55 kg walks into a room and sees a girl 8.0 m in front of him who has a mass of 40 kg. What is his gravitational attraction to her?
A. 
B. 
C. 
D. 
E. 