According to the law of conservation of energy, which statement must be true?
1 answer:
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Answer:
Explanation:
<u>Motion in The Plane</u>
When an object is launched in free air with some angle respect to the horizontal, it describes a known parabolic path, comes to a maximum height and finally drops back to the ground level at a certain distance from the launching place.
The movement is split into two components: the horizontal component with constant speed and the vertical component with variable speed, modified by the acceleration of gravity. If we are given the values of and
as the initial speed and angle, then we have
If we want to know the maximum height reached by the object, we find the value of t when becomes zero, because the object stops going up and starts going down
Solving for t
Then we replace that value into y, to find the maximum height
Operating and simplifying
We have
The maximum height is
Answer:
Explanation:
The angular momentum of an object in rotation is given by
where
I is the moment of inertia
is the angular speed
In this problem, initially we have
is the moment of inertia of the wheel
is the initial angular speed
So the initial angular momentum is
Later, a counterclockwise torque of
is applied
So the angular acceleration of the wheel is:
in the direction opposite to the initial rotation.
As a result, the final angular velocity of the wheel will be:
where
t = 4.0 is the time interval
Solving,
which means that now the wheel is rotating in the counterclockwise direction.
Therefore, the new angular momentum of the wheel is:
So, the change in angular momentum is:
- Mass=m=20kg
- Radius=r=4m
- Velocity=10m/s=v
We know