71.Block 2 shown below slides along a frictionless table as block 1 falls. Both blocks are attached by a frictionless pulley. Find the speed of the blocks after they have each moved 2.0 m. Assume that they start at rest and that the pulley has negligible mass. Use m₁ = 2.0 kg and m₂ = 4.0 kg. 20

5. A top WNBA player can jump about .7 meters off the ground. If her mass is 50 kg, what force must she exert against the ground? Assume she crouches a distance of .2 metes prior to jumping, and thus the upward force has this distance to act before leaving the ground. 6. A block is given an initial speed of 4 meters per second up the 0 = 22° plane shown below. Ignoring friction, %3D (a) how far up the plane will it go? (b) How much time elapses before it returns to its starting point? R 4m/s s 22°

6. Two packages that start sliding down a 20° ramp from rest a distance d = 4.30 m. For package A: Ma = 5.00 kg and ukA = 0.30. %3D For package B: mB = 7.00 kg and ukB = 0.20. Find the speed of both packages when they reach the bottom. 20°

4. Here we prove a version of the work-kinetic energy theorem for an object moving in 1-D subject to a constant force. Consider a mass m, traveling initially at speed v, on which a constant net force F is applied in the same direction as its motion over a distance d. After the net force has acted over this distance, the speed of the object is v2. In terms of m, F, v1, v2, and d only, V, A) What is the acceleration of the mass? t=0 m F d t>0_m B) What is the time over which the mass travels the V, distance d? [Use one equation of constant acceleration to find this.] C) Use another equation of constant acceleration to relate m, F, v,, v2, and d. Show that the product W = Fd is equal to the change in the mass’s kinetic energy.