Gravitational potential energy:UG=-GMmR

7. For satellite of massm=100 kg in a circular Earth orbit (20 km above Earth's surface)

a. what is the gravitational potential energy of the satellite? b. what is the kinetic energy of the satellite?

c. What is the escape velocity at that altitude (20 km)?

38. (II) The forearm in g. 1052 accelerates a 16-\" ball at 7.01M? by means of the triceps muscle. as shown. Calculate (a) the torque needed. and (b) the force that must be exerted by the tn'eeps muscle. Ignore the mass 31 cm] _. of the arm. 2. 53. (III) A hammer thrower accelerates the hammer (mass = 7.30 kg) from rest within four full turns (revolutions) and releases it at a speed of 26.5 m/s. Assuming a uniform rate of increase in angular velocity and a horizontal circular path of radius 1.20m, calculate (a) the angular acceleration, (b) the (linear) tangential acceleration, (c) the centripetal acceleration just before release, (d) the net force being exerted on the hammer by the athlete just before release, and (e) the angle of this force with respect to the radius of the circular motion. Ignore gravity