A two-car train, with data as given in Fig. is pulled by a child on a horizontal frictionless surface. The strings are massless. The force exerted by car A on the string S is:
Correct answer: D. 15N
- A. 10N
- B. 20N
- C. Zero
- D. 15N
Explanation
To solve this problem, use Newton's second law, F = ma. First, find the total mass of the two-car system. Then, determine the acceleration by dividing the total force applied by the total mass. Since the surface is frictionless, the force exerted by car A on the string S is equal to the mass of car A multiplied by the common acceleration. The correct force is 15N. Other options are incorrect because they either do not consider the entire system or miscalculate the acceleration.
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Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
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