Explanation:
Given that,
The initial velocity of a skater is, u = 5 m/s
She slows to a velocity of 2 m/s over a distance of 20 m.
We can find the acceleration of skater. It is equal to the rate of change of velocity. So, it can be calculated using third equation of motion as follows :

a = acceleration

So, her acceleration is  and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.
 and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.
 
        
             
        
        
        
Answer:
Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.
Newton's second law states that the acceleration of an object is directly related to the net force and inversely related to its mass. Acceleration of an object depends on two things, force and mass.
Newton's third law states that if an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.
Explanation:
 
        
             
        
        
        
The magnetic field at the center of the arc is  4 × 10^(-4) T.
To find the answer, we need to know about the magnetic field due to a circular arc. 
<h3>What's the mathematical expression of magnetic field at the center of a circular arc?</h3>
- According to Biot savert's law, magnetic field at the center of a circular arc is 
-  B=(μ₀ I/4π)× (arc/radius²)
-  As arc is given as angle × radius, so
         B=( μ₀I/4π)×(angle/radius)
<h3>What will be the magnetic field at the center of a circular arc, if the arc has current 26.9 A, radius 0.6 cm and angle 0.9 radian?</h3>
B=(μ₀ I/4π)× (0.9/0.006)
   = (10^(-7)× 26.9)× (0.9/0.006)
   = 4 × 10^(-4) T
Thus, we can conclude that the magnitude of magnetic field at the center of the circular arc is 4 × 10^(-4) T.
Learn more about the magnetic field of a circular arc here:
brainly.com/question/15259752
#SPJ4
 
        
             
        
        
        
Answer:
θ = 13.16 °
Explanation:
Lets take mass of child = m
Initial velocity ,u= 1.1 m/s
Final velocity ,v=3.7 m/s
d= 22.5 m
The force due to gravity along the incline plane = m g sinθ
The friction force = (m g)/5
Now from work power energy
We know that
 work done by all forces = change in kinetic energy
( m g sinθ - (m g)/5 ) d = 1/2 m v² - 1/2 m u²
(2  g sinθ - ( 2 g)/5 ) d = v² -  u²
take g = 10 m/s²
(20 sinθ - ( 20)/5 ) 22.5 = 3.7² -  1.1²
20 sinθ - 4 =12.48/22.5
θ = 13.16 °
 
        
             
        
        
        
You just multiply these two numbers. It's 5200J, or 5.2kJ