8) I agree with student 1 who says that there only two forces acting on student 3, the normal force and weight force. That means these two forces are Newton's third law pairs(equal in magnitude and opposite in direction).
9) Mass of the block is 2.77 kg
10) The force needed to make this system move is 600,000 N
Explanation:
8. The weight of the book acts as a downward force and the table on which the book is lying exerts a normal force in the upward direction on the book. The weight W and normal force N are equal in magnitude and opposite in direction. Hence I agree with Student 1.
9)Given:
Force=10 N
Acceleration (a)=3.6 m/sec2
Solution:
[tex]F=ma\\\\m=F/a\\\\=10/3.6\\\\=2.77 kg[/tex]
Thus the Mass of the block is calculated to be 2.77 kg.
10)Given:
Mass of the train1=3000 kg.
Mass of train 2=3000 kg.
Solution:
Total mass of the system=3000+3000=6000 kg
acceleration a =100m/sec^2
Force needed to make this system move is given by
[tex]F=ma\\6000\times 100=600,000 N[/tex]
Thus 600,000 N force is needed to make this system move.
