As an electromagnetic wave travels through free space, its speed can be increased by:
a. increasing its frequency.
b. increasing its energy only.
c. increasing both its energy and momentum.
d. None of the above will increase its speed.
D
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What is the wavelength of light that has a frequency of 3 MHz?
a. 9 × 10^14 Hz b. 1 × 10^14 m c. 9 × 10^14 m d. 100 m e. 0.01 m
How far does light travel in a century?
A. 
B. 
C. 
D. 
E. 
Suppose a baseball travels 425 ft (130 m) from where the batter hits it to where it lands in the stands. The ball’s velocity makes an angle of 40° with respect to the horizontal as the ball leaves the bat. Suppose we first calculate the ball’s initial speed ignoring drag and find it to be . Including drag might plausibly require a higher initial speed for the ball to travel the same horizontal distance. On the other hand, by slowing down the ball’s vertical motion, including drag will increase the ball’s flight time, allowing the ball the same distance with a slower horizontal velocity. So if we include drag, for the ball to fly the same horizontal distance will we need
A. An initial speed greater than 
.
B. An initial speed less than .
C. An initial speed equal to .
D. More information to answer for sure.
A 1321-kg car climbs a 5.0° slope at a constant speed of 80km/s Assuming that air resistance may be neglected, at what rate (in kW) must the engine deliver energy to the drive wheels of the car?
A) 25 kW B) 48 kW C) 287 kW D) 38 kW