A radio station's signal has a radius of 100 miles. If you drive at a constant speed of 40 miles an hour, nonstop, directly across the diameter of the signal, how long can you listen to the station before the signal fades?
The radius is 100 miles . . . so the diameter is 200 miles (100 miles towards the transmitter and 100 miles going away.
At 40mph it takes 5 hours to drive 200 miles, therefore you could listen to the station for 5 hours.
You can listen to the station for 5 hours before the signal fades
Acceleration is rate of change of velocity.
\(\large {\boxed {a = \frac{v - u}{t} } }\)
\(\large {\boxed {d = \frac{v + u}{2}~t } }\)
a = acceleration ( m/s² )
v = final velocity ( m/s )
u = initial velocity ( m/s )
t = time taken ( s )
d = distance ( m )
Let us now tackle the problem!
Given:
Radius of Signal = R = 100 miles
Speed of Car = v = 40 miles/hour
Unknown:
Time Taken = t = ?
Solution:
\(\texttt{Time Taken} = \texttt{Distance} \div \texttt{Speed of Car}\)
\(\texttt{Time Taken} = \texttt{Diameter of Signal} \div \texttt{Speed of Car}\)
\(\texttt{Time Taken} = \texttt{2 x Radius of Signal} \div \texttt{Speed of Car}\)
\(\texttt{Time Taken} = 2 \times 100 \div \texttt{40}\)
\(\texttt{Time Taken} = 200 \div 40\)
\(\texttt{Time Taken} = 5 \texttt{ hours}\)
Grade: High School
Subject: Physics
Chapter: Kinematics
Keywords: Velocity , Driver , Car , Deceleration , Acceleration , Obstacle , Signal , Radio , Station , Fade , Nonstop