Câu 5. Một vật dao động điều hòa với phương trình x = 20cos(10pit +pi/2) (cm). Xác định thời điểm đầu tiên vật đi qua vị trí có
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Answer:
The answer is ""
Explanation:
velocity of car | respect to car :
Answer:
average speed = 66.67 km/h
Explanation:
In order to find the average speed of the train, you need to calculate the total distance traveled, divided by the time it took to cover that distance. So for the total distance:
Distance= 120 km + 180 km = 300 km
For the total time we need to add three different quantities, two of which we need to derived based on the information provided:
time for first part of the trip:
for the time of the stop:
for the last part of the trip:
Which gives a total of 4.5 hours
Then, the average speed is: 300/4.5 km/h = 66.67 km/h