Tug of War

Who will win? Add pullers to each side of the rope, then pull and watch the forces battle it out.

Puller to add
Left team
2 · 600 N
Right team
3 · 800 N
Net force
200 N →
Acceleration
0.19 m/s²
Speed
0.00 m/s
Flag moved
0.00 m

The maths, live

Net force F = Right − LeftF = 800 − 600 = 200 N
Heel grip f = μ × m × gf = 0.1 × 140 × 9.81 = 137 N
Newton's 2nd law a = (F − f) ÷ ma = (200 − 137) ÷ 323 = 0.19 m/s²

Make the two teams pull with exactly the same force. Does the flag move? Now add one kid to one side.

How it works

Each team pulls the rope towards itself. When both teams pull equally hard, the forces are balanced: the net force is zero and the rope stays still. When one team pulls harder, the forces are unbalanced and the rope starts to move towards the stronger team.

The leftover force is the net force. Newton's second law says it speeds up everything attached to the rope: a = F ÷ m, where m is the mass of both teams and the rope. The losing team digs its heels into the ground, and that friction can hold back a small difference in pull.

Try this

  1. Make the two teams pull with exactly the same total force. Does the rope move?
  2. Can three kids beat two adults? What about two strong adults?
  3. Start a pull, then add pullers to the losing side. Can they stop the rope?