activity 11.5 9 th class science
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Answer:
Which book? ncert? Plz specify it
1st ) According to Newton's first law of motion, an object will move.only when an unbalancedforce acts in it. So in your question, since the object is moving, it implies a certainforce is acting on it.
2) Work is basically a form of energy, so in general, when the work is done on an object it must result in a change of its energy. The simplest case is mechanical work: we could accelerate the object, or move it around in a gravitational orelectric potential field—-but there are other forms of work that are less obvious.
3) If a force is applied but theobject doesn't move, no work is done; if a force is applied and the object moves a distance d in a direction other than the direction of the force, less work is done than if the object moves a distance d in the direction of the applied force.
1) Three examples when force being supplied and still there is no displacement are:
(i) A man pushing a stationary truck.
(ii) A man pushing a rigid wall.
(iii) Aboy carrying a basket on his head and standing still. Here, force of gravity acts on the basket, but there is no displacement.
2) when the object is moving at a constant velocity. when we keep the ball or any other object in the inclined plane or in the slanting surface it move to the another point that isdisplacement without any external force acting on it. so there can be displacementwithout any force acting on it.