An object of mass 2 kg moving with a constant velocity of 10 m s⁻¹ encounters a rough patch where the force of friction on the object is 7 N. At the same time, an additional constant force of 3 N opposing the motion is applied on the object. After entering the rough patch, how much distance does the object travel before coming to rest?
10 m
Explanation
The problem requires calculating the net retarding force, then the deceleration using Newton's second law, and finally the distance using the kinematic equation = + 2as. The textbook context provides examples of calculating net force and acceleration (Example 6.5) and using kinematic equations (Example 6.6).
Solution Steps
Step 1: Calculate the net opposing force: F = 7 N + 3 N = 10 N
Step 2: Calculate the acceleration using F = ma: a = F/m = 10 N / 2 kg = 5 m/s². Since it opposes motion, a = -5 m/s²
Step 3: Use the kinematic equation v² = u² + 2as to find distance: 0 = (10)² + 2(-5)s
Step 4: Solve for s: 0 = 100 - 10s => 10s = 100 => s = 10 m