Problem 1
A bullet of mass travels horizontally at speed through a stationary wooden block of mass . After exiting, the bullet has speed . The block then slides on a rough horizontal surface with kinetic friction coefficient . Find the block's speed immediately after the interaction and its stopping distance. Model each stage with the appropriate conservation law or equation of motion; quantities stated as constant remain fixed during that stage. (a) Establish the governing physical relation for each stage. (b) Determine the requested observables from the stated initial conditions and constraints. (c) Check signs, dimensions, and the physical limiting behavior of the results.
problems.proof.stepOf
problems.proof.analysis
The block receives the bullet's momentum loss; solve for . This follows from the chosen physical model and the stated initial conditions; the sign convention must remain consistent throughout. A dimensional check catches algebraic errors before the result is interpreted.
problems.proof.pitfall. Do not mix sign conventions or omit a system constraint; check the sign and units before interpreting the result.