A constant force acting on a body of mass 3.0 kg changes its speed from 2.0 ms-1 to 3.5 ms-1 in 25 s. The direction of the motion of the body remains unchanged. What is the magnitude and direction of the force?
Mass of the body, m = 3 kg Initial speed of the body, u = 2 m/s Final speed of the body, v = 3.5 m/s Time, t = 25 s Using the first equation of motion, the acceleration (a) produced in the body can be calculated as: v=u+at a=t(v−u) =25(3.5−2)=0.06m/s2 As per Newton's second law of motion, force is given as: F=ma =3×0.06=0.18N Since the application of force does not change the direction of the body, the net force acting on the body is in the direction of its motion.
