pls answer all 4 questions .If you don't know pls don't answer .
Answers
Answer:
1.The force acting on wooden block is gravatational and pressure of air and friction of threat
2. The block will Not fell down in that possotion because thread has caughted the block
3.yes if the thread is broken the block will fall down due to gravitational pull of earth
4.after reaching the ground gravatational and pressure of air is acting
1 Scientific curiosity was a major motive behind Western overseas expansion from the fifteenth century onward and technological innovations, particularly in shipbuilding, navigational instruments, and firearms, made that expansion possible. But early European explorers and conquistadors did not rely heavily on evidence of scientific or technological achievements as gauges of the worth of the peoples they encountered or as explanations for their growing dominance in the Americas and maritime Africa and Asia. In encounters with the great centers of civilization in Africa and Asia, European superiority in these endeavors was highly selective, marginal, or in many areas nonexistent. In fact, travelers to China and the Indian subcontinent in the early centuries of expansion were as likely to dwell on the technological deficiencies of the West, when compared to these great civilizations, as to boast of European advantages. As in India, China, and Japan, the Europeans were able to make little...
Since this block is in equilibrium (at rest with zero acceleration), the net vector force must be zero Newtons. This means the net force in the x direction and the net force in the y direction must be zero. What forces are acting in the y direction? It's just the gravitational force and the frictional force. Yes, the magnitude of the frictional force must be equal to the weight. The friction is in the vertical direction because it is parallel to the wall (which is vertical).
2 Image may contain Text Handwriting Label Cushion and Pillow
So the pushing force (F above) increases the normal force (N) and this normal force increases the friction force to balance the weight. I'll skip the rest of the steps (you should do this for homework), but in the end, the minimum force (which uses the maximum friction) would be:
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3 Let us calculate the work done in lifting an object of mass m through a height h, such as in Figure 1. If the object is lifted straight up at constant speed, then the force needed to lift it is equal to its weight mg. The work done on the mass is then W = Fd = mgh. We define this to be the gravitational potential energy (PEg) put into (or gained by) the object-Earth system. This energy is associated with the state of separation between two objects that attract each other by the gravitational force. For convenience, we refer to this as the PEg gained by the object, recognizing that this is energy stored in the gravitational field of Earth. Why do we use the word “system”? Potential energy is a property of a system rather than of a single object—due to its physical position. An object’s gravitational potential is due to its position relative to the surroundings within the Earth-object system. The force applied to the object is an external force, from outside the system. When it does positive work it increases the gravitational potential energy of the system. Because gravitational potential energy depends on relative position, we need a reference level at which to set the potential energy equal to 0. We usually choose this point to be Earth’s surface, but this point is arbitrary; what is important is the difference in gravitational potential energy, because this difference is what relates to the work done. The difference in gravitational potential energy of an object (in the Earth-object system) between two rungs of a ladder will be the same for the first two rungs as for the last two rungs.
4 Strippers can be expensive. Stop thinking rap stars, lap dances and sports celebrities. We are talking about a “stripper” in terms of a hole that has had its threads stripped out or damaged. In addition to being expensive to repair, strippers also require a great deal of time and usually evoke a great deal of frustration. Fortunately, understanding the history of the materials being threaded along with the science of inserts can help you avoid encountering a stripper or, at least, be prepared to select the correct parts to repair a stripper. Done right, you’ll never have a thread failure in the same hole again.
5 Force
In the previous chapter, we described the motion of an object along a straight line in terms of its position, velocity and acceleration. We saw that such a motion can be uniform or non-uniform. We have not yet discovered what causes the motion. Why does the speed of an object change with time? Do all motions require a cause? If so, what is the nature of this cause? In this chapter we shall make an attempt to quench all such curiosities.
For many centuries, the problem of motion and its causes had puzzled scientists and philosophers. A ball on the ground, when given a small hit, does not move forever. Such observations suggest that rest is the 'natural state' of an object. This remained the belief until Galileo Galilei and Isaac Newton developed an entirely different approach to understand motion.