Da VIP Academy / GED / Science / Physical Science
Forces & Motion
Apply Newton's laws and compute speed, acceleration, and force.
How it works
Newton's laws in plain words
1) Objects keep doing what they are doing unless a force acts. 2) F = ma — more force means more acceleration, more mass means less. 3) Forces come in equal, opposite pairs.
Speed and acceleration
Speed = distance ÷ time. Acceleration = change in velocity ÷ time. A car going 60 mph at a steady speed has zero acceleration even though it is moving fast.
Worked examples
A 4 kg cart accelerates at 3 m/s². What net force acts on it?
- F = ma.
- F = 4 × 3.
- F = 12 newtons.
Words to know
- Net force
- The total force after opposing forces cancel.
- Inertia
- An object's resistance to a change in motion.
Test-day tips
- • Constant speed in a straight line = zero net force.