Imagine you are running PE class. You run the first 1000 meters in 3 minutes and then get tired and run the last 600 meters in 5 minutes. What was your *average* speed?

Va = 3.77 [m/s]

Explanation:

We know that speed is defined as the relationship between the distance traveled in a given time.

v = L/t

where:

v = speed [m/s]

L = distance = 1000 [m]

t = time = 3 [min] = 180 [s]

Therefore the first speed is:

v = 1000/180

v = 5.55 [m/s]

Now the second velocity:

t = 5 [min] = 300 [s]

v = 600/300

v = 2 [m/s]

The average speed is calculated by the sum of both speeds divided by two.

Va = (5.55 + 2) /2

Va = 3.77 [m/s]

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