Answer:
Anna is correct.
Explanation:
Anna is right as a satellite is in free fall because it keeps falling toward Earth, meaning that gravity is the only force acting on it. Tom is incorrect because an object does not have to accelerate at a certain speed to be considered to be in free fall. As long as gravity is the only force acting upon the object, it is considered to be in free fall.
The velocity of the wave on the string is given by

Solving the above equation,

The frequency of the wave
and wave length is 
The velocity is 
Substituting numerical values,

The length of the string is 
Answer:
support lights as a wave
Explanation:
In the model of light as a particle, the experimenter would expect to see one small hole of light emerging on the wall. However, as the light spreads out, it behaves much like a wave that diffracts when going through a small hole.
It is either 98 J or 98 N let me check..
Answer:
Ffriction = 217.7[N]
Explanation:
First, we must find the mass of the box, we must remember that the weight is defined as the product of the mass by acceleration.

where:
w = weight [N] (units of Newtons)
m = mass [kg]
g = gravity acceleration = 9.81 [m/s²]
![1300=m*9.81\\m=132.51[kg]](https://tex.z-dn.net/?f=1300%3Dm%2A9.81%5C%5Cm%3D132.51%5Bkg%5D)
Now we must use Newton's second law, which tells us that the sum of forces is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F sum of forces
m = mass = 132.51[kg]
a = acceleration = 1.3[m/s²]
We must know that the forces that act are the horizontal force that moves the box and the friction force in the negative direction that acts against the movement.
Now replacing:
![390-f_{friction}=132.51*1.3\\390-172.26=f_{friction}\\f_{friction}=217.7[N]](https://tex.z-dn.net/?f=390-f_%7Bfriction%7D%3D132.51%2A1.3%5C%5C390-172.26%3Df_%7Bfriction%7D%5C%5Cf_%7Bfriction%7D%3D217.7%5BN%5D)