Physics Group Exercise: Conservation of Linear Momentum and Energy in a Collision - Prof. , Study notes of Physics

Download Physics Group Exercise: Conservation of Linear Momentum and Energy in a Collision - Prof. and more Study notes Physics in PDF only on Docsity! Physics 2414 Group Exercise 9 Name 1: OUID 1: Name 2: OUID 2: Name 3: OUID 3: Name 4: OUID 4: So lu tio ns So lu tio ns Section Number: Conservation of Linear Momentum Conservation of Energy: The sum of change in kinetic energy ∆K and the change in potential energy ∆U equals the work done by the non-conservative forces. ∆K + ∆U = Σ Wnc. (1) Momentum: A mass m moving with a velocity ~v has a momentum ~p = m~v associated with it. Conservation of linear momentum: If there is no external forces acting on a system, the total linear momentum of the system is conserved. If ~Fnet = 0, ~pftot = ~pitot. (2) Problems A skier with mass M1 = 75 kg starts from rest at point ‘1’ at a height H = 50 meters from the ground. Assume frictionless surfaces all throughout this problem. 1 H 1 2 1. Before collision: Find the velocity v2 of the skier when he reaches point ‘2’. ∆K12 + ∆U12 = Σ W 12nc (3) ( 1 2 M1v 2 2 − 0) + (0 − M1gH) = 0 (4) v2 = √ 2gH (5) = √ 2 × 9.8 × 50 = 31.3m/s (6) 2. Conservation of linear momentum: The skier keeps moving on the horizontal frictionless surface with velocity v2. The skier collides into a box of mass m2 = 25 kg at point ‘c’. After the collision the skier grabs the box and then moves with the box as a single entity with velocity v3. H 1 2 c 3 (a) What is the initial momentum ~p1i of the skier just before the collision? ~p1i = M1v2 = 75 × 31.3 = 2347 N sec (7) (b) What is the initial momentum ~p2i of the box just before the 2