Answer:
Explanation:
A general wave function is given by:
A: amplitude of the wave = 0.075m
k: wave number
w: angular frequency
a) You use the following expressions for the calculation of k, w, T and λ:
b) Hence, the wave function is:
c) for x=3m you have:
d) the speed of the medium:
you can see the velocity of the medium for example for x = 0:
Answer:
The friction force is 250 N
Explanation:
The desk is moving at constant velocity. This means that its acceleration is zero: a = 0. Newton's second law states that the resultant of the forces acting on the desk is equal to the product between mass (m) and acceleration (a):
In this case, we know that the acceleration is zero: a = 0, so also the resultant of the forces must be zero:
(1)
We are only interested in the forces acting along the horizontal direction, since it is the direction of motion. There are two forces acting in this direction:
- the pull, forward, F = 250 N
- the friction force, backward,
Given (1), we have
So the force of friction must be equal to the pull: