1. A sledge loaded with bricks has a total mass of 18.7 kg and is pulled at constant speed by a rope inclined at 19.5° above the horizontal. The sledge moves a distance of 20.1 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500. (a) What is the tension in the rope? N (b) How much work is done by the rope on the sledge? kJ (c) What is the mechanical energy lost due to friction? kJ
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.
1. A sledge loaded with bricks has a total mass of 18.7 kg and is pulled at constant speed by a rope inclined at 19.5° above the horizontal. The sledge moves a distance of 20.1 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500.
N
(b) How much work is done by the rope on the sledge?
kJ
(c) What is the mechanical energy lost due to friction?
kJ
J
(b) Determine the work done by the friction force between block and incline.
J
(c) Determine the work done by the normal force.
J
(d) Qualitatively, how would the answers change if a shorter ramp at a steeper angle were used to span the same vertical height?
N
(b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.
s
N/m
(b) If the 2.70-kg object is removed, how far will the spring stretch if a 1.35-kg block is hung on it?
cm
(c) How much work must an external agent do to stretch the same spring 7.00 cm from its unstretched position?
J
J
(b) Suppose the projectile is traveling 89.3 m/s at its maximum height of
J
(c) What is the speed of the projectile immediately before it hits the ground if air friction does one and a half times as much work on the projectile when it is going down as it did when it was going up?
m/s
m
(b) If the track is not frictionless, would the spring's maximum compression be greater than, less than, or equal to the value obtained in part (a)?
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