Only one of the following is possible for a moving object. Which one? The velocity is directed eastward and is decreasing, while
1 answer:
Answer:
The velocity is zero at one instant, and the acceleration is not zero at that instant.
Explanation:
We know that
Where
a is the acceleration of moving object
V is the velocity.
When velocity of object is increasing with time then it means that object is accelerated.
When velocity of object is decreasing with time then it means that object is de-accelerated.
When velocity is constant it means that acceleration of object is zero.
So at particular position the instant velocity of block is zero but acceleration is not zero at that instant.
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(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.
Recall that
We have , so that
(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.
(c) The ball's average velocity is 0. Average velocity is given by , and we know that
.
(d) The position of the ball at time
is given by
Take the starting position to be the origin, . Then after 6 seconds,
so the ball is 42 m away from where it started.
We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:
Since the velocity is positive, the ball is still moving up the incline.