This question is a short free-response question. Show your work for each part of the question. A person pushes a large block on a horizontal ice surface in a straight line to the right with constant speed, as shown above. The mass of the block is 10kg and frictional forces between the block and the ice are negligible. However, the block has a wide cross-sectional area such that air resistance acting on the block cannot be neglected. The opposite is true for the person: air resistance on the person is negligible, but the person’s shoes do not slip on the ice. The table shows the force exerted by the person on the block for several values of constant speed. (a) A student claims that the data show that the magnitude of the force of air resistance is proportional to the speed of the object, within experimental uncertainty. Use physics principles to explain whether the claim is correct. (b) As the person pushes the block, the person moves with the same constant speed as the block. Consider the scenario in which the person’s speed is 5.00 m/s. i. On the dot below, which represents the person, draw and label the forces (not components) exerted on the person. Each force must be represented by a distinct arrow starting on, and pointing away from, the dot.
Kinematics
A machine is a device that accepts energy in some available form and utilizes it to do a type of work. Energy, work, or power has to be transferred from one mechanical part to another to run a machine. While the transfer of energy between two machine parts, those two parts experience a relative motion with each other. Studying such relative motions is termed kinematics.
Kinetic Energy and Work-Energy Theorem
In physics, work is the product of the net force in direction of the displacement and the magnitude of this displacement or it can also be defined as the energy transfer of an object when it is moved for a distance due to the forces acting on it in the direction of displacement and perpendicular to the displacement which is called the normal force. Energy is the capacity of any object doing work. The SI unit of work is joule and energy is Joule. This principle follows the second law of Newton's law of motion where the net force causes the acceleration of an object. The force of gravity which is downward force and the normal force acting on an object which is perpendicular to the object are equal in magnitude but opposite to the direction, so while determining the net force, these two components cancel out. The net force is the horizontal component of the force and in our explanation, we consider everything as frictionless surface since friction should also be calculated while called the work-energy component of the object. The two most basics of energy classification are potential energy and kinetic energy. There are various kinds of kinetic energy like chemical, mechanical, thermal, nuclear, electrical, radiant energy, and so on. The work is done when there is a change in energy and it mainly depends on the application of force and movement of the object. Let us say how much work is needed to lift a 5kg ball 5m high. Work is mathematically represented as Force ×Displacement. So it will be 5kg times the gravitational constant on earth and the distance moved by the object. Wnet=Fnet times Displacement.
This question is a short free-response question. Show your work for each part of the question.
A person pushes a large block on a horizontal ice surface in a straight line to the right with constant speed, as shown above. The mass of the block is 10kg and frictional forces between the block and the ice are negligible. However, the block has a wide cross-sectional area such that air resistance acting on the block cannot be neglected. The opposite is true for the person: air resistance on the person is negligible, but the person’s shoes do not slip on the ice. The table shows the force exerted by the person on the block for several values of constant speed.
(a) A student claims that the data show that the magnitude of the force of air resistance is proportional to the speed of the object, within experimental uncertainty. Use physics principles to explain whether the claim is correct.
(b) As the person pushes the block, the person moves with the same constant speed as the block. Consider the scenario in which the person’s speed is 5.00 m/s.
i. On the dot below, which represents the person, draw and label the forces (not components) exerted on the person. Each force must be represented by a distinct arrow starting on, and pointing away from, the dot.
ii. The person now stops and releases the block. Determine the magnitude and direction of the block’s acceleration at the instant the block is released.
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