Baseball scouts use a radar gun to measure the speed of pitches. One particular model of radar gun emits a microwave signal at a frequency of 10.525 GHz (GHz = x10^9 Hz). What is the increase in frequency of these waves as seen by a 40.2 m/s fastball headed straight toward the radar gun? (Express your answer in the following format: #.# x 10^# Hz)

Explanation:

We are given that

Frequency,f=

Speed,v=40.2 m/s

We have to find the increase in frequency.

We know that

Speed of light,c=

The waves are reflected therefore the change in frequency  at the gun is equal to twice the change in frequency.

Therefore, increase in frequency=

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27