Problem 1 A goalkeeper kicks a ball of mass 400 g in the air, and reaches a posi
ID: 1987082 • Letter: P
Question
Problem 1 A goalkeeper kicks a ball of mass 400 g in the air, and reaches a position of height 15.9 m above the ground corresponding to a horizontal distance 19.7 m from its initial position. During its flight, the ball experiences a horizontal friction force of 3 N from a wind blowing opposite to the horizontal direction of its motion. 1) What is the work done by the gravitational force on the ball? 2) What is the work done by the friction force on the ball? 3) What is the total work done on the ball?Explanation / Answer
1)Work done by gravity = m*g*h = 0.4* 15.9 * 9.8 = 62.3Joules 2)Work done by friction force = F * s = 3 * 19.7 = 59.1 Joules 3)Total work done on the ball = 1+2 = 121.4