Sliding friction is harder to overcome, and steals
more energy whenever you're moving.
That's why we switched from sleds to wheels
several thousand years ago.
If the boat's velocity is 18m/sec relative to the water in the river and not the shore, it would need to be added the river speed of 2.5m/sec to get a total of 20.5m/sec. The 20.5m/sec would then be the total velocity of the boat relative to the shore. From personal experience, I know that when one runs with the tide, one is adding the tide flow speed to one's boat speed (what it would be in neutral waters) to get a sometimes much faster speed.
Answer:
An object's acceleration is the rate its velocity (speed and direction) changes. Therefore, an object can accelerate even if its speed is constant - if its direction changes.
Explanation:
The dog walked 5 meters backwards in the first 10 seconds, then 5 meters forward from 10-20 seconds. After 20 sec he was back where he started. Displacement (20sec) = zero.
Answer:
19,551 J!
Explanation:
The formula is PE = ham (h=height, a= acceleration or 9.8, m= mass)
PE = (95)(9.8)(21)
PE = 19,551 Joules
