Find average speed in time interval t = 2 tot = 10s
Distance (m)
10+
8-
2
+ Time (s)
10

3.75 m/s

Explanation:

Average speed is distance covered per time taken.

If the time interval is from t = 2 to t = 10s

Then, the time taken will be

t = 10 - 2 = 8s

Given that the distance covered are 10 + 8 - 2 + 10

Since distance is a scalar quantity, we will only consider the magnitude and not the direction.

Total distance = 10 + 8 + 2 + 10 = 30m

Average speed = total distance/time

Substitute total distance and time into the formula

Average speed = 30/8

Average speed = 3.75 m/s

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000