mary walked north from her home to sheila's home, which is 4.0 kilometers away. then she turned right and walked another 3.0 kilometers to the supermarket, which is 5.0 kilometers from her own home. she walked the total distance in 1.5 hours. what were her average speed and average velocity?

Speed = 4.67 km/h

Velocity = 3.33 km/h

Explanation:

Part a)

As Mary walk Towards North for 4 KM

and then she turns right and walk another 3 KM

so the net displacement of the Mary from her house is given as

while the total distance moved by her

now average speed is defined as

Part b)

average velocity is the ratio of displacement and time

the answer is b, have negligible mass

radiation

explanation:

heat is transmitted by radiation