An athlete with a mass of 60.5 kg is in a cross country race, and at one instant he has a speed of 5.40 m/s. (a) What is his kinetic energy at this instant? KE = (b) If he wishes to doubles his speed to reach the finish line, his kinetic energy will change by what factor? KE+ KE The center fielder for the school's baseball team throws a 0.150-kg baseball towards home plate at a speed of 32.0 m/s and an initial angle of 40.0. What is the kinetic energy of the baseball at the highest point of its trajectory? J Supporting Materials Physical Constants A.022. TEACHER Consider a system of a cliff diver and the earth. The gravitational potential energy of the system decreases by 28,000 J as the diver drops to the water from a height of 34.0 m. Determine her weight in newtons. Submit Answer N 2. [-/1 Points] DETAILS OSCOLPHYS1 7.P.026.WA. A pendulum bob with a mass of 0.39 kg is attached to a 1.5 m long string as shown. 8 1.5 m MY NOTES ASK YOUR TEACHER B As the pendulum bob swings from point A, where the angle = 40, to point B at the bottom of its arc, determine the change in the gravitational potential energy of the pendulum bob-earth system. Supporting Materials Physical Constants Submit Answer 3. [-/3 Points] DETAILS OSCOLPHYS1 7.P.025.WA. MY NOTES ASK YOUR TEACHER A child with a weight of 130 N swings on a playground swing attached to 2.20 m long chains. What is the gravitational potential energy (in J) of the child-earth system relative to the child's lowest position at the following times? (a) when the chains are horizontal ] (b) when the chains make an angle of 27.0 with respect to the vertical (c) when the child is at his lowest position Supporting Materials Physical Constants Submit Answer 4. [-/4 Points] DETAILS OSCOLPHYS2016 7.3.WA.024. MY NOTES ASK YOUR TEACHER While leaning out a window that is 5.9 m above the ground, you drop a 0.60 kg basketball to a friend at ground level. Your friend catches the ball at a height of 1.8 m above the ground. Determine the following. (a) the amount of work done (in J) by the force of gravity on the ball (b) the gravitational potential energy (in J) of the ball-earth system, relative to the ground when it is released (c) the gravitational potential energy (in J) of the ball-earth system, relative to the ground when it is caught (d) the ratio of the change (PE - PE) in the gravitational potential energy of the ball-earth system to the work done on the ball by the force of gravity W