Since this is a distance/time graph, the speed at any time is the slope 
of the part of the graph that's directly over that time on the x-axis.
At time  t1 = 2.0 s
That's in the middle of the first segment of the graph, 
that extends from zero to 3 seconds.
Its slope is  7/3 .              v1 = 7/3 m/s .
At time  t2 = 4.0 s
That's in the middle of the horizontal part of the graph 
that runs from 3 to 6 seconds. 
Its slope is zero. 
                                     v2 = zero .
At time  t3 = 13 s.
That's in the middle of the part of the graph that's sloping down, 
between 11 and 16 seconds.
Its slope is  -3/5 .            v3 = -0.6 m/s .               
        
                    
             
        
        
        
Answer:
the layers of atmosphere are heated through radiation and convection.
Explanation:
- heat is transferred from sun through radiation
- and current through convection
 
        
                    
             
        
        
        
If you increase the frequency of a sound wave four times, t<span>he speed will increase four times. The correct option among all the options that are given in the question is the first option or option "A". This also shows the frequency and speed of the waves are directly proportional to each other. I hope it helps you.</span>
        
                    
             
        
        
        
Answer:
a) 4.2m/s
b) 5.0m/s
Explanation:
This problem is solved using the principle of conservation of linear momentum which states that in a closed system of colliding bodies, the sum of the total momenta before collision is equal to the sum of the total momenta after collision.
The problem is also an illustration of elastic collision where there is no loss in kinetic energy.
Equation (1) is a mathematical representation of the the principle of conservation of linear momentum for two colliding bodies of masses  and
 and  whose respective velocities before collision are
 whose respective velocities before collision are  and
 and  ;
;

where  and
 and  are their respective velocities after collision.
 are their respective velocities after collision.
Given;

Note that  =0 because the second mass
=0 because the second mass  was at rest before the collision.
 was at rest before the collision.
Also, since the two masses are equal, we can say that  so that equation (1) is reduced as follows;
 so that equation (1) is reduced as follows;

m cancels out of both sides of equation (2), and we obtain the following;

a) When  , we obtain the following by equation(3)
, we obtain the following by equation(3)

b) As  stops moving
 stops moving  , therefore,
, therefore,
