Answer:
The frictional force
6.446 N
The acceleration of the block a = 6.04 
Explanation:
Mass of the block = 3.9 kg
°
= 0.22
(a). The frictional force is given by


3.9 × 9.81 × 
29.3 N
Therefore the frictional force
0.22 × 29.3
6.446 N
(b). Block acceleration is given by

F = 30 N
= 6.446 N
= 30 - 6.446
= 23.554 N
The net force acting on the block is given by

23.554 = 3.9 × a
a = 6.04 
This is the acceleration of the block.
Dredging is what the inventor of this machine need to know while developing the machine.
Hope this helps!
Answer:
0.625 c
Explanation:
Relative speed of a body may be defined as the speed of one body with respect to some other or the speed of one body in comparison to the speed of second body.
In the context,
The relative speed of body 2 with respect to body 1 can be expressed as :

Speed of rocket 1 with respect to rocket 2 :



Therefore, the speed of rocket 1 according to an observer on rocket 2 is 0.625 c
When a woman walks south at a speed of 2.0mph for 60 minutes. She then turns around and walks north at a distance of 3000m in 25 minutes. then the woman's average speed during her entire motion would be 73.15 meters /minute.
<h3>What is speed?</h3>
The total distance covered by any object per unit of time is known as speed.
the mathematical expression for speed is given by
speed = total; distance /total time
As given in the problem a woman walks south at a speed of 2.0mph for 60 minutes
60 min = 1 hour
1 mile = 1.60934 km
The distance covered by her southwards = speed ×time
=2 mph × 60 minutes
= 3.218 km
She then turns around and walks north at a distance of 3000m in 25 minutes
The distance covered northward is 3000m
speed = total distance /total time
=(3218 +3000) /(60+25)
=73.15 meters /minutes
Thus, The average speed of the woman would be 73.15 meters /minute.
Learn more about speed from here
brainly.com/question/13263542
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