An object is thrown vertically and has an upward velocity of 18 m/s when it reaches one fourth of its maximum height above its launch point. What is the initial (launch) speed of the object?
a. 35 m/s
b. 25 m/s
c. 30 m/s
d. 21 m/s
e. 17 m/s
d
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When an antimatter particle meets its matching particle of normal matter, the two particles annihilate each other and convert their mass back into energy in the form of two _____
A) alpha rays B) cosmic rays C) gamma rays D) beta rays
Light strikes a diamond (n = 2.42) at an angle of 60° relative to the normal to the surface. What is the angle of refraction?
a. 21° b. 30° c. 38° d. 69° e. 71°
One of the most efficient engines built so far has the following characteristics: combustion chamber temperature = 1900°C, exhaust temperature = 430°C, 7.0 × 109 cal of fuel produces 1.4 × 1010 J of work in one hour
(a) What is the actual efficiency of this engine? (b) What is the Carnot efficiency of the engine? (c) What is the power output, in hp, of this engine?
When a wave crosses from one medium into another in which the wave speed is lower, the frequency is unchanged. The wavelength
A. decreases. B. stays the same. C. increases.