Questions on force

1.       F= ma = 2000 x 3 = 6000 N

2.       F= ma = 90 x (-4) = -360 N

3.       F= ma = 0.05 x 60 = 300 N

4.       F = ma = 10 000 000 kg x 10 = 100 000 000 N = 1 x 10⁸ N

5.       F = ma = 70 x 14 = 980 N

6.       F= ma = 1000 x 50 = 50 000 N

7.       F = ma = 0.1kg x 5 = 0.5 N

 

Newton's third law of motion (force pairs)

See here

http://twyfordigcsephysics.blogspot.co.uk/2012/12/newton-3.html