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A constant force acting on a body of mass 3.0 kg changes its speed from 2.0 m s–1 to 3.5 m s–1 in 25 s. The direction of the motion of the body remains unchanged. What is the magnitude and direction of the force? |
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Answer» 0.18 N; in the direction of motion of the body 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 = (v - u)/t = (3.5 - 2)/25 = 1.5/25 = 0.06 m/s2 As per Newton’s second law of motion, force is given as: F = ma = 3 × 0.06 = 0.18 N 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. |
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