You and a friend are swimming upstream while towing an inner tube containing a basket in which there is a delightful picnic lunch. As you swim, you produce a force of 4.6 E 2 N upstream. The current produces a force of 6.7 E 2 N downstream. The mass of the inner tube, basket, and delightful picnic lunch is 9.6 kg. If the inner tube accelerates at 1.2 m/s? upstream, determine the upstream force provided by the swimming of your friend.