Question

True-False (2 points each). Circle the correct answer. 1) D F An isolated system has a net external force of zero. 2)TF Momentum is conserved in an isolated system. 3) TT The definition of work is W = Fdcos(0) 4) T (F) The spring force is proportional to the displacement of the spring end. 5) O T Engines and generators can be 100% efficient. 6) DF The impulse is equal to the change in momentum. 7) DF In an isolated system energy can be transformed, but never lost or created. 8) D F Heat is the transfer of energy from a hotter to colder object. 9) DF Kinetic energy is conserved in an isolated system. 10) F Gravitational potential energy depends on speed. Conceptual Questions (4 points each). 11) Which block has the largest momentum? a) b) c) d) 4 e) 5. 10 12) The small block collides and sticks to the larger block What is the speed of the two blocks after the collision? a) Vi b) 4/5 c) 5/4 d) 2v; 13) A parachutist is coming down at constant speed. The parachutist's gravitational potential energy is being converted to a) kinetic energy b) thermal energy c) kinetic and thermal energy d) there is no energy conversion 14) Suppose you climb a flight of stairs and increase your gravitational potential energy by 1400 J. Assume the efficiency of your body is 25%. How much metabolic energy did your body generate to climb the stairs? FIN) 8001 Point of maximum compression 400- 200- Contact Contact 15) In the graph at the right the impulse is represented by a) the value of maximum compression b) the slope where contact begins c) the slope where contact ends d) the area under the curve begins ends. 0 20 80 100 40 60 Duration Ar Dr. Villanueva

Answer 1

1.T o An isolated system has a net exkemal forlen 25o. 2.0 t momentum is conserved in an isolated a system. 3. A & The definition of work we F & coro- 4. 6 F The Spring force is propertionat the displacement of the sprind end. 5. I Engines and generators efficients. 6. A The impulse is equal to to the change in momentum. T. O lu on isolater system energy con be Iransformed, but never lost or wanted. 8. G F Heat is transfer of energy from a hotter to colder object. d. & kinetic energy is conserved in an isoked system. 10 T Gravitational poteeltal senorsy depews on speed. 11). Momentum defined as pa meiss (m) & velocity (6) pam 2= 2 20.02kgings 1. 20x1 = 5o = 0.02 kg.oys 3.4 X2 = 0.04 kg. nls. S. 5. 200 1011 2 2 2 2. 20 x 2 = 25 ore 1000 x 2 = 100 = 0.02 kg. 20.01 kg. m/s 4. 10 x 1 mm s Too 0.04kg. Bls. largest momentum b) 2

12. from Conservation of unean momentun my Wi + zm vi = (with me Smriz 4 m c) or vi – after the collision. 13. A Par achalist is coming dow Come fart speed. The para charlists potential enersy is being gravitational converted to a) kinetic enersy. I am not stole to do answer sorry 14) & 15