The true scientific way is the last: using the water displacement method
Answer:
3 m/s
Explanation:
average speed = distance traveled / total time taken
= 6m/ 2s
= 3 m/s
Suppose car A is moving with a velocity Va, and car b with a velocity Vb,
According the principle of conservation of momentum:
Va x Ma + Vb x Mb = (Ma + Mb) V
V = (Va x Ma + Vb x Mb)/(Ma +Mb)
V = speed of cars after coupling
V = (Va x 20 mg + Vb x 15 mg)/(20 mg + 15 mg)
Put in the values of Va and Vb, and get the V
Gravity is pulling the book towards the center of the earth, and the rebounding effect of the table cancelling out gravity allowing for the book to sit at rest.
