There are two questions I need answers for please. These arereview questions for a test. 1. A string is 50cm long. When the ball it released from restit swings along the dotted arc. How fast is it going when itreaches the lowest point in its swing? 2. A projectile of mass .50 kg is fired with an initial speedof 10 m/s at an angle of 60 degrees above the horizontal. Thepotential energy of the projectile earth system (relative to whenprojectile is at ground level) is what? There are two questions I need answers for please. These arereview questions for a test. 1. A string is 50cm long. When the ball it released from restit swings along the dotted arc. How fast is it going when itreaches the lowest point in its swing? 2. A projectile of mass .50 kg is fired with an initial speedof 10 m/s at an angle of 60 degrees above the horizontal. Thepotential energy of the projectile earth system (relative to whenprojectile is at ground level) is what?
Explanation / Answer
mass ofthe projectile m = 0.50 kg initial speed u = 10 m/s angle of projection = 60deg maximum height of theprojectile H = u2 sin2 60 / 2g = 100x 0.75 / 2 x 9.8 = 3.82m potential energy relative to earth at maximum height H = mgH = 0.50 x 3.82 x 9.8 = 18.718 J