A body of mass 17.5 kg is moving on a straight path at a constant speed of 6.5 m/s. At an instant, a constant force acts on the body for 5 s which changes its speed to 3.5 m/s in opposite direction. What is the magnitude of force acting on the body?
(1) 10.5 N
(2) 28 N
(3) 42 N
(4) 35 N
