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Force Calculator

Force Calculator is part of Toolspire and is ready as soon as this page loads. This is Newton’s second law for a constant mass: F = m a. It is the net force, after the pushes and pulls have been added with their signs.

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What you can do here

Net force

Do not type one push if a friction force is also acting, unless you already subtracted it.

The weight check is in the copy, not a second mode

Swap 3 for 9.81 yourself to see weight. The page will not assume you meant weight.

Newtons when the units match

Kilograms and metres per second squared.

The sequence

How to use the Force Calculator

  1. 1

    Use the net acceleration

    If several forces act, either sum them first or type the resulting acceleration.

  2. 2

    Check 6

    Two times three.

  3. 3

    For weight, type g as the acceleration

    9.81, not 3, if you want the gravitational force on that mass.

Worth knowing

  • Force Calculator on Toolspire: F = m a.
  • 2 kg × 3 m/s² = 6 N.
  • Weight is the special case a = g. A 2 kg mass weighs about 19.62 N if g is 9.81.
  • A negative acceleration is a deceleration in the positive direction, and the force comes back negative.

The product is the net force

Newton’s second law, for a mass that is not changing, says the net force equals mass times acceleration. Two kilograms at three metres per second squared is six newtons. The six newtons are whatever remains after every force has been added. Typing a single engine force while friction still acts will overstate the acceleration you would really see. The page multiplies the two numbers and does not draw a free-body diagram.

FAQ

Questions about Force Calculator

Where does Force Calculator run?

Force Calculator runs in this tab on Toolspire. What you type or drop in is not sent to us and is not stored on a server.

What force accelerates 2 kg at 3 m/s²?

6 newtons.

How do I get weight?

Use acceleration 9.81 m/s². For 2 kg that is 19.62 N.

What does a negative force mean?

The net force points opposite the direction you called positive.

Does this include friction?

Only if your acceleration is the real resulting acceleration, or you already folded friction into the force you are checking.

Keep going

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