AP Physics 1 · Unit 2, Part 1 · Forces

Newton’s Second Law Practice Problems

Use net force and mass to explain acceleration. Compare controlled force and mass changes, then solve problems involving opposing forces, braking, different gravitational fields, and an angled force.

12 questions6 conceptual · 6 calculation

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Simulation scene from the Newton’s Second Law lesson. — A scene from the related lesson. Open the practice to work through the questions.

What you’ll practice

Use the combined forces to predict acceleration

Compare force and mass trials

Predict how acceleration changes when net force doubles or when the same force acts on a larger mass. Keep the controlled quantity fixed.

Find the net force

Combine opposing and angled forces before applying Newton’s second law. Solve for an unknown force, mass, or acceleration.

Connect force with a velocity change

Analyze a tug slowing down and a raft moving through acceleration and steady-speed stages. Distinguish velocity direction from acceleration direction.

A question from this set

Twice the net force

A 3.0 kg cart starts from rest on a level track with negligible friction. In a second trial, the horizontal net force is doubled while the cart’s mass stays the same. How does its acceleration compare?

It stays the same.
It doubles.
It is cut in half.

Try it in the practice set

Both trials use a 3.0 kg cart; the second has twice the horizontal net force.

Key ideas

The vector sum determines the acceleration

Use ΣF = ma

The acceleration belongs to the selected object or system and follows its net external force. A large individual force can be partly canceled by another force.

Change one quantity at a time

At fixed mass, acceleration is proportional to net force. At fixed net force, increasing mass reduces acceleration. Compare otherwise identical trials to isolate the relationship.

See the physics

Compare acceleration under different force settings

Check your prediction, then run paired force or mass trials from rest. Inspect velocity changes and force arrows, or compare the braking interval with the direction of acceleration.

Use a hint for a starting point or open a worked solution to follow the reasoning. Your progress saves in this browser, so you can return to unfinished questions.

Ready for newton’s second law?

Begin with a conceptual question, then work through the calculations.

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