C: if it senses unequal currents
Answer: 
Explanation:
In the image attached with this answer are shown the given options from which only one is correct.
The correct expression is:

Because, if we derive velocity
with respect to time
we will have acceleration
, hence:

Where
is the mass with units of kilograms (
) and
with units of meter per square seconds
, having as a result 
The other expressions are incorrect, let’s prove it:
This result has units of
This result has units of
This result has units of
and
is a constant
This result has units of
This result has units of
This result has units of
and
is a constant
This result has units of
and
is a constant
because
is a constant in this derivation respect to
This result has units of
and
is a constant
Answer:
number 3 The wind because the wind has strong pressure which causes to change peoples directions in where they are going
Explanation:
hope this helped by the way i think you answered b and 4 i don't know if this is a test and i sent this at the wrong time :(
Answer:
Friction between the box and the floor is 25N to the left
Explanation:
There are two forces acting on the box along the horizontal direction:
- The force of push applied by the worker, in the forward direction, F
- The force of friction,
, acting in the opposite direction (backward)
So the net force acting on the box is

According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:

And so

However, in this case the box is moving at constant speed; this means that its acceleration is zero:

Therefore we have:

Which means

And since we are told that

This means that the force of friction is also 25 N:

Answer:+1.25 m/s
Explanation:
Given
mass of ice skater M=70 kg
mass of ball m=10 kg
the initial velocity of the ball 
Conserving linear momentum
![M\times0+m\timesu_1=(M+m)v\quad \quad [v=\text{combined velocity of skater and ball}]](https://tex.z-dn.net/?f=M%5Ctimes0%2Bm%5Ctimesu_1%3D%28M%2Bm%29v%5Cquad%20%5Cquad%20%5Bv%3D%5Ctext%7Bcombined%20velocity%20of%20skater%20and%20ball%7D%5D)

Therefore the velocity of the person holding the ball is 1.25 m/s
This collision represents the perfectly inelastic collision where particles stick together after the collision.