Question

A soccer player kicks a soccer ball of mass 0.45 kg that is initially at rest. The player's foot is in contact with the ball for 1.40 x 103 s, and the force of the kick is given by F(t) = [(7.20 x 105)t - (5.14 x 108)+21 N for Osts 1.40 X 10's, where t is in seconds. Find the magnitudes of the following: (a) the impulse on the ball due to the kick, (b) the average force on the ball from the player's foot during the period of contact, (c) the maximum force on the ball from the player's foot during the period of contact, and (d) the ball's speed immediately after it loses contact with the player's foot. (a) Number Units (b) Number Units (c) Number Units (d) Number Units

Answer 1

al quan m=0.45kg T=1.40xlo's (3) - 07.0X105) - (514x108) a) the impulse on the ball due to the kick I T Float T[ (7.20x1050- (s. 14x108) I²dt (7.2 0X105 3 7 2 _ (514x108) I} = (1.20x16T (1.40X163) 2 (5:14X108) (1 4oxias I= 0.25NS I 6) the average force on the ball from the players's foot dining the period of contact - IT 20.235 c) the maximum choot during force on the ball from the players. hoat during the period of Contact = fm df - 17.2010) 2(5.14x108)+=0 [t= 7.00 3X10 45 T 1. 40x1.3 =) 168-18- Ay dt

So tm r 1.4 Xlo 3) = (720x05) (5 14X108) +2. = (720X108) (1.40x103) (5 14K 109) (1.4001032 = 10.56) d) the ball's speed immediatelly after ad loses, Contact with the player's foot = v mr=I = v= I/m 0.235 0.45 V = 0.522 mis