The equivalent of Newton's second law for rotational objects is given by:
where
is the net torque acting on the object
is its moment of inertia
is its angular acceleration
For a hoop rotating around its perpendicular axis, the moment of inertia is
where m is the mass and r the radius. By using the data of the wheel, m=0.750 kg and r=33.0 cm=0.33 m, we find
and since the torque is
, the angular acceleration of the wheel is
D. The flow of energy,heat, and work
Answer:
a) 0.32 m b) -2.4 m c) 1.08 m/s d) -4 m/s
Explanation:
a)
- As the x and y axes (as chosen) are perpendicular each other, the movements along these axes are independent each other.
- This means that we can use the kinematic equations for displacements along both axes.
- In the x direction, as the only initial velocity is in the south direction (-y axis), the skateboarder is at rest, so we can write:
- In the y-direction, as no acceleration is acting on the skateboarder, we can write the following displacement equation:
- For t = 0.6s, replacing by the givens, we get the position (displacement from the origin) on the x-axis, as follows:
b)
- From (2) we can get the position on the y-axis (displacement from the origin) as follows:
c)
- In the x- direction, we can find the component of the velocity along this direction, as follows:
- Replacing by the values, we have:
d)
- As the skateboarder moves along the y-axis at a constant speed equal to her initial velocity, we have:
vfy = voy = -4 m/s
Answer:
if somthing is warm or if somthing moves it usally has energy