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PHYS16 – Lecture 20 Review: Ch. 1-7 October 25, 2010 Administration • TA Help Sessions – Su 8-9 pm, W 8-9 pm, Sa 3-5pm – Merrill 116 (around the corner from my office) • Online Homework 8 due Sunday, Oct. 31 • Formal Lab Report due Monday, Nov. 1 Review Ch. 5 Energy Practice Question 1 • I throw ball #1 up with an initial speed of v0, and I throw ball #2 of equal mass down with an initial speed of v0. Just before the balls hit the ground what is the relationship of their kinetic energies? A) B) C) D) K1>K2 K1=K2 K1<K2 There is not enough information Practice Question 2 • F(x)=3x^2+4. What is the work done from x = 1 m to x=3 m? A) B) C) D) 34 J 31 J 33 J 18 J Practice Question 3 • A 300 kg car slows from 60 km/s to 10 km/s. What is the work done on the car? A) B) C) D) 5.25E11 J -5.25E8 J -5.25E5 J -5.25E11 J Practice Question 4 • Which object has more kinetic energy? A) B) C) D) E) 1 kg, 5 m/s 2 kg, 4 m/s 3 kg, 3 m/s 4 kg, 2 m/s 5 kg, 1 m/s Practice Question 5 • Which object has more momentum? A) B) C) D) E) 1 kg, 5 m/s 2 kg, 4 m/s 3 kg, 3 m/s 4 kg, 2 m/s 5 kg, 1 m/s Practice Question 6 • A horizontal force of 60 N slides a block up a 10 m incline of 30 degrees. Ignore friction. What is the work done by the force to get the block up the ramp? A) 60*10*cos(30) B) 60*10*sin(30) C) 60*cos(30) D) 60*sin(30) Ch. 6 Energy Conservation Practice Question 1 • A 50-kg kid is sliding down a ramp with a height of 4 m and a horizontal distance of 3 m. If the frictional force is a constant 60 N, what is the velocity of the kid at the bottom of the ramp? Practice Question 2 • A mass is attached to a horizontal spring of spring constant 4N/m. If a weight attached to the mass pulls the mass a distance of 0.5 m from equilibrium, how much work was done by the weight on the mass? Ch. 7 Momentum Practice Question 1 • In a perfectly inelastic collision the following is not true? A) Objects adhere B) E is conserved C) P is conserved D)F=dp/dt Practice Question 2 • True or false. In an inelastic collision the kinetic energy after the collision can be greater than the kinetic energy before the collision. A) True B) False Practice Question 3 • In a click-clack if all balls have equal mass and I take one ball out and put it at height 4 m, how high should the ball on the other side go? A) 4 m B) 2 m C) 0 m D)There is not enough information