Answer:
W=1055N
Explanation:
In order to solve this problem, we must first do a drawing of the situation so we can visualize theh problem better. (See attached picture)
In this problem, we will ignore the board's weight. As we can see in the free body diagram of the board, there are only three forces acting on the system and we can say the system is in vertical equilibrium, so from this we can say that:
so we can do the sum now:
when solving for the Weight W, we get:
and now we can substitute the given data, so we get:
W=410N+645N
W=1055N
Explanation:
Below is an attachment containing the solution.
Kinetic energy is calculated by using formula:
Ek = 1/2*m*v^2
Now we replace values of mass and speed in this formula.
Ek = 1/2*10*3^2 = 45.0J
When you have a formula and all variable values are given in the text of question just replace variable values in equation and find the final value.
To solve this exercise we need the concept of Kinetic Energy and its respective change: Initial and final kinetic energy.
Let's start considering that the angular velocity is given by,
Where,
V = linear speed
R = the radius
In the case of the initial kinetic energy:
Where I is the moment of inertia previously defined.
In the case of the final kinetic energy, we have to,
For conservation of Energy we have, that
, then (canceling the mass and the radius)