A hand pushes a wall with \(40\,\mathrm{N}\) to the right. State the force of the wall on the hand.

Are the weight of a book and the normal force on the book a third-law pair?

Earth pulls downward on a \(2.0\,\mathrm{kg}\) object. State the third-law partner force.

Two skaters push apart. If skater A exerts \(60\,\mathrm{N}\) on skater B, what force does B exert on A?

Two carts push apart with force magnitude \(20\,\mathrm{N}\). Cart A has mass \(2.0\,\mathrm{kg}\), cart B has mass \(5.0\,\mathrm{kg}\). Find each acceleration magnitude.

A \(0.040\,\mathrm{kg}\) ball and a \(2.0\,\mathrm{kg}\) launcher exert equal \(30\,\mathrm{N}\) forces on each other. Find both acceleration magnitudes.

A runner pushes the ground backward with one foot. What force from the ground helps the runner accelerate forward?

Two carts start from rest and push apart for \(0.50\,\mathrm{s}\) with force magnitude \(12\,\mathrm{N}\). The carts have masses \(2.0\,\mathrm{kg}\) and \(3.0\,\mathrm{kg}\). Find their speeds after the push and the displacement each cart travels during the push.

Two carts on a frictionless track start from rest with a compressed spring between them. During release, each feels an average force of \(18\,\mathrm{N}\) for \(0.40\,\mathrm{s}\). Cart A has mass \(1.5\,\mathrm{kg}\); cart B has mass \(3.0\,\mathrm{kg}\). Find their final velocities, check total momentum, and compare kinetic energies.

A \(65\,\mathrm{kg}\) skater pushes a \(45\,\mathrm{kg}\) skater with \(90\,\mathrm{N}\) for \(0.80\,\mathrm{s}\), starting from rest on level ice. During the same push, the lighter skater experiences a constant drag of \(12\,\mathrm{N}\) opposite motion, the heavier skater has negligible drag. Find both final speeds and directions.