Your hand is warmed when you blow on it with your mouth open, but when your lips are puckered so that air expands as you blow, your hand is
A) warmer still.
B) cooler.
C) neither warmer nor cooler.
Answer: B
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A brass rod of length L 5 0.75 m is twisted by torques T until the angle of rotation between the ends of the rod is 3.58. The allowable shear strain in the copper is 0.0005 rad. The maximum permissible diameter of the rod is approximately:
(A) 6.5 mm
(B) 8.6 mm
(C) 9.7 mm
(D) 12.3 mm
A boat moves at 10.0 m/s relative to the water. If the boat is in a river where the current is 2.0 m/s, how long does it take the boat to make a complete round trip of 1.00 km upstream followed by a 1.00 km trip downstream?
What will be an ideal response?
What is the speed of a proton that has been accelerated from rest through a potential difference of 4.0 kV?
A. 1.1 × 106 m/s B. 9.8 × 105 m/s C. 8.8 × 105 m/s D. 1.2 × 106 m/s E. 6.2 × 105 m/s
An unstable particle initially at rest breaks up into two fragments. The mass of one fragment is 1.75 × 10^–28 kg and the mass of the other fragment is 1.25 × 10^–27 kg. The lighter fragment has a speed of speed 0.850c. What is the speed of the heavier fragment?
a. 0.229c b. 0.119c c. 0.127c d. 0.220c