as per the question charlie runs to the store which is 4 km away
hence the total distance covered [S] is 4 km
he takes 30 minutes to reach the store.
hence the total time taken [t] = 30 minutes=0.5 hour
We have to calculate the average speed.
the average speed[v]= 
=
=8 km/hour
then we have to calculate the total distance traveled by charlie in 1 hour.
the distance covered S= 
=8 km/hour ×1 hour
=8 km
Hence the average speed of charlie is 8 km/hour and he covers a distance of 8 km in 1 hour.
Let's see: frequency of cellular phone waves (GSM phones) is (800-1900 MHz). If we look at the table of the electromagnetic spectrum, we can see that this range is contained within the frequencies of the microwaves, which include waves in the range 300 MHz-300 GHz.
So, summarizing, the correct answer is "microwaves".
I got B,when you subtract 3/5 from NEGATIVE 2/3 it creates a negative 19 over a positive 15.
Answer: I think Its the Height is 11.76 Meters (38.582677 Feet) between the bridge and the ground
Explanation: Supposing that where not counting air resistance in the equation, the equation 
states that 1/2 multiplied by earths gravitational acceleration multiplied by the amount of time to reach the bottom: 2.4 seconds equals 11.76 meters of height between the bridge and the ground.
Answer:
Yes such a frame exists: a free-fall (free-float frame) frame. This frame of reference is subject only to gravity and no forces such as electromagnetic forces or nuclear forces.
