A distance-time graph indicates that an object moves 20 m in 10 s and then remains at rest for 20s. What is the average speed of the object?

v = 2 m/s

Explanation:

The object moves 20 m in 10 s initially. Then it remains at rest for 20 s. It is required to find the average speed of the object.

Fro 10 s it covers 20 m. For that time, speed is :

For 20 s, it was at rest means distance covered is 0. So, speed is 0.

The average speed of the object is equal to the sum of speed for 10 s and for 20 s i.e.

v = 2 m/s + 0 = 2 m/s

So, the average speed of the object is 2 m/s.

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation: