In the real world, it is difficult to find a situation where no forces are acting on an object. Class 9

In the real world, it is difficult to find a situation where no forces are acting on an object. Class 9

Question 1.

In the real world, it is difficult to find a situation where no forces are acting on an object. But by applying additional forces, a condition can be achieved where the net force on the object is zero. Explain with the help of an example. Class 9

Answer:

Example: Consider a box being pushed across the floor at a constant velocity. Two forces act on the box: the applied force (forward) and the force of friction (backward). If the magnitude of the applied force is made exactly equal to the force of friction, the two forces are equal and opposite, so the net force on the box is zero. Even though forces are present, the net force is zero - and the box moves with constant velocity (Newton's first law).

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Question 2.

A toy car of mass 100 g is moving with a constant velocity of 0.5 m s^-1. What is the net force acting on the toy car? Class 9

Answer:

The toy car is moving with constant velocity. By Newton's first law, constant velocity means acceleration is zero. Using F = ma: F = 0.1 kg × 0 = 0 N. The net force acting on the toy car is zero.