Work, energy and power — Grade 12 Past Paper Questions

A 12 kg block on a rough incline is pulled upward by constant force, reaching 4.5 m higher with speed 2.25 m·s⁻¹. Apply energy methods to find work done by non-conservative forces and the distance along the incline.

A 6 kg crate is pushed at 30° to horizontal by constant force on a horizontal surface with 10 N friction. Over 1.5 m it reaches 2 m·s⁻¹. Calculate the force using energy principles and analyse the effect of adding mass.

A 20 kg crate is hauled from rest up an 18° slope by a motor, with a 96.8 N force along the incline against 13.5 N of friction over 15.6 m. Find the speed, the average power, and what happens once the rope snaps.

A 6 g bullet at 200 m·s⁻¹ embeds itself in a stationary 194 g wooden block. Calculate the system's velocity after impact and its deceleration on a rough surface.

A 2 kg box released from 5 m height slides down a smooth curved track and then 10 m across rough horizontal surface before hitting a barrier at 4 m·s⁻¹. Calculate speeds and forces using energy principles and impulse-momentum theory.

An electric pump lifts 200 kg of water vertically from 12.5 m below ground at constant speed. Calculate the work done by the pump, the lifting speed, and the average power dissipated.

A block with unknown mass enters a horizontal region with 3 N friction at 8 m·s⁻¹ over 4 m, then travels 5.03 m up a 30° incline with 2 N friction to rest. Apply energy principles to derive the final speed and find the mass.

A 62 kg person on a sandboard accelerates from 8.5 m·s⁻¹ to 23.3 m·s⁻¹ over a sand dune with 8,700 J of friction work. Calculate the starting height using energy methods, define power, and find average force from power data.

Multiple-choice page covering power dissipation when a car travels at constant velocity on a horizontal road, and momentum and energy analysis for a block-pulley system with friction.

Multiple-choice questions on kinetic energy changes when a ball collides with a wall and rebounds, and work done by forces on an object on a rough incline.

Multiple-choice page covering net forces in projectile motion, conservation laws in inelastic collisions, work-energy relationships, Doppler effect, and electrostatic forces.

Multiple-choice questions on momentum conservation when a person jumps from a skateboard, total mechanical energy of falling objects, and wavelength changes in the Doppler effect.

Multiple-choice page covering the work-energy theorem and forces on objects sliding down inclines, and power and efficiency of a motor pulling a crate up a slope.