Physics Exam Tested Questions with Accurate Answers Guaranteed to get an A (2025 Version).

Physics Exam Tested Questions with Accurate Answers Guaranteed to get an A (2025 Version). For a particular spring, the spring constant: -Increases as the spring is stretched. -Increases as the spring is compressed. -Decreases as the spring is compressed. -Is the same regardless of stretching or compressing. Is the same regardless of stretching or compressing. Hooke's law relates: -The spring force to the force used to compress the spring. -The spring force to the change in the length of the spring. -Change of the length of the spring to gravity. -Change of the length of the spring to the metal the spring is made of. The spring force to the change in the length of the spring. If the net force on an object is zero: -The net torque is zero. -The acceleration is zero. -The frictional force is zero. -The acceleration is decreasing. The net torque is zero. The spring force is: -In the same direction as the change in the spring's length. -In the opposite direction as the change in the spring's length. -Perpendicular to the change in the spring's length. -Constant regardless of the change in the spring's length. In the opposite direction as the change in the spring's length. An object can remain balanced if: -Its center of gravity is over the pivot point. -Its center of gravity is to the right of the pivot point. -Its center of gravity is to the left of the pivot point. -Its mass is equally distributed. Its center of gravity is over the pivot point. For an object in static equilibrium: -The net torque about any point is zero. -The net torque about every point is different. -The net torque about every point is a nonzero constant. -None of the above. The net torque about any point is zero. In order for an object to be in static equilibrium: -The net force equals zero. -The net torque equals zero. -Either the net force or the net torque equal zero. -Both the net force and the net torque equal zero. Both the net force and the net torque equal zero. The spring force is larger: -The more the spring is stretched. -The more the spring is compressed. -All of the above. -None of the above. All of the above. What factors contribute to improving the stability of an object? -Wider base -Lower center of gravity -All of the above -None of the above All of the above Inelastic collisions occur when: -Bonds between the objects are broken. -There is no compression during the collision. -The masses are all the same. -The objects stick together. The objects stick together. In order for the angular momentum of a rotating object to be conserved: -Net torque must be zero. -Net force must be zero. -Net torque must be a constant not equal to zero. -Net force must be a constant not equal to zero. Net torque must be zero. We have an expert-written solution to this problem! The impulse of an interaction can be defined as: ___________. F avg x change in time The momentum of an object is: _____________. Mass x velocity Impulse can be defined as: -Change of velocity -Change of mass -Change of angular position -Change of momentum Change of momentum In a collision, one way to decrease the force of impact is to: -Decrease the time of the impact -Increase the time of the impact -Increase the momentum -Decrease the momentum Increase the time of the impact The total momentum of a system is conserved if: -There are no external forces acting on the system -There are no internal forces acting within the system -The velocities don't change -The masses don't change There are no external forces acting on the system An example of conservation of angular momentum is: -Jumping off a diving board -A car going around a corner -An ice skater changing the speed of a spin -A golf club hitting a golf ball An ice skater changing the speed of a spin Angular momentum is defined as: ___________________. Moment of inertia x angular velocity In two-deminsional collisions, momentum conservation is: -In the x direction only -In the y direction only -In the x or y direction, but not both -In both the x and y directions In both the x and y directions What is conserved in a perfectly elastic collision? Momentum and energy Power refers to: -How fast work is done -The strength of the force doing the work -The amount of energy transfers -The amount of work done relative to the energy used to do it How fast work is done Kinetic energy: -Depends on the speed of the object -Depends only on the mass of the object -Depends on the speed an mass of the object -Is not in this chapter Depends on the speed and the mass of the object Kinetic energy of a rolling object: -Is greater than that of a non-rotating object with the same speed -Is the same as a non-rotating object with the same speed -Is less than that of a non-rotating object with the same speed -Is zero Is greater than that of a non-rotating object with the same speed Work is done: -By any force -By the component of the force perpendicular to the displacement -By the component of the force parallel to the displacement -Only if the entire force is parallel to the displacement By the component of the force parallel to the displacement How does gravitational energy depend on the height, h, of an object: -mgh -mh -mgh^2 -mh^2 mgh Forms of potential energy include: -Kinetic and gravitational -Thermal and elastic -Kinetic and thermal -Gravitational and elastic Gravitational and elastic Energy conservation tells us that the energy of a system can change via: -Work done on or by the system -Heat transfer -Both a and b -None of the above Both a and b Given the distance x that a spring is compressed, what is the potential energy of the spring? -1/2 kx -1/2 kx^2 -2 kx -2 kx^2 1/2 kx^2 How many calories are in 1 Calorie? 1000 How does heat spontaneously move? from high temperature to low temperature The temperature of an ideal gas is a measure of: -The total kinetic energy of the atoms -The average kinetic energy of the atoms -The maximum kinetic energy of the atoms -The minimum kinetic energy of the atoms The average kinetic energy of the atoms When energy is said to be lost due to inefficiencies in the energy transformation, what has happened to the energy? It has transformed to a form that isn't useful The efficiency of a heat engine: -Is always 100% -Is usually 100% -Depends on the process -Is never 100% Is never 100% The efficiency of a typical human body (according to the book) is ______. 25% The 2nd Law of Thermodynamics says: -The entropy of an isolated system always decreases -Total entropy never decreases -Total entropy can decrease for certain processes -Nothing about entropy Total entropy never decreases Absolute zero is: -The temperature at which water freezes -Different for different temperature scales -The point at which the kinetic energy of the atoms is zero -Not real. It only exists in science fiction The point at which the kinetic energy of the atoms is zero What symbol is used for heat? Q What happens to entropy when energy is transformed to thermal energy? It increases An object at rest is in _______________. static equilibrium Discuss the conditions for static equilibrium of an extended object. No net force No net torque For an object in static equilibrium, the net torque about every point must be _______. zero As long as the object's center of gravity remains over the base of support, torque due to gravity will rotate the object back toward its stable equilibrium position; we say that the object is _________. stable The gravitational torque causes a rotation in the opposite direction and the car rolls over; the object is ________. unstable What can improve stability? -A wider base of support -A lower center of gravity a force that restore a system to an equilibrium position restoring force systems that exhibit restoring forces elastic What are some examples of elasticity? -Springs -Rubber bands What is the symbol for the spring constant? k What are the units of k? N/m a property that characterizes a spring, just as the mass m characterizes a particle spring constant (k) Discuss the difference between k being large and k being small. -If k is large, it takes a large pull to cause a significant stretch, and we call the spring a "stiff" spring. -If k is small, we can stretch the spring with very little force, and we call it a "soft" spring. Steel is elastic, but under normal forces, it experiences only very small changes in dimension. Materials of this sort are called _________. rigid materials that show large deformations with small forces pliant a property of the material from which the rod is made - it does not depend on shape or size Young's modulus (Y) the ratio of force to cross-section area stress the ratio of the change in length to the original length strain the largest stress that the material can sustain before breaking tensile strength As long as the stretch stays within the linear region, a solid rod acts like a spring and obeys _____________. Hooke's law An object is ________ if its center of gravity is over its base of support. stable a short-duration interaction between two objects collision a large force exerted during a short interval of time impulsive force change in momentum impulse the product of the object's mass and velocity momentum states that an impulse delivered to an object causes the object's momentum to change impulse-momentum theorem If the duration of the collision can be increased, then the ________ of the impact will be decreased. force forces that act only between particles within the system internal forces forces from agents outside the system external forces If F net = 0, then the ________ momentum of the system does not change. total With no net external force acting that can change its momentum, we call a system with F net = 0 an __________________. isolated system The total momentum of an isolated system is a constant. Interactions within the system do not change the system's total momentum. Law of conservation of momentum the particles of the system move apart after a brief, intense interaction explosion a collision in which the two objects stick together and move with a common final velocity perfectly inelastic collision What is the symbol for angular momentum? L What is the equation for angular momentum? L = Iw product of moment of inertia rotating at angular velocity angular momentum the sum of the different kinds of energies preset in the system total energy Energy transformations are changes of energy ________ the system from one form to another. within an exchange of energy between system and environment energy transfer What are the two primary energy-transfer processes? 1. Work 2. Heat the mechanical transfer of energy to or from a system by pushing or pulling on it work the nontechnical transfer of energy from the environment to the system (or vice versa) because of a temperature difference between the two heat The total energy of an isolated system remains constant. Law of conservation of energy a system that is separated from its surrounding environment in such a way that no energy is transferred into or out of the system isolated system For an isolated system, is there any work done on the system? no The larger the displacement, the __________ the work done. greater The stronger the force, the ________ the work done. greater What is the unit for work? Joules (J) an object's energy of motion kinetic energy shows how our energy model is modified to include energy transfers into and out of the system as well as energy transformations within the system basic energy model the kinetic energy of an object movie along a line or some other path translational kinetic energy the kinetic energy due to rotation rotational kinetic energy The kinetic energy of a ________ object is always greater than that of a __________ object moving at the same speed. rolling; nonrotating stored energy that can later be converted into other forms of energy potential energy interaction forces that can store useful energy conservative forces What kind of force is friction? nonconservative force What are examples of conservative forces? Gravity and elastic forces Gravitational potential energy depends only on the ________ of an object and not on the path the object took to get to that position. height energy that is stored in a compressed or extended spring elastic (spring) potential energy the sum of microscopic potential ad kinetic energies thermal energy Discuss conservation of energy. For an isolated system, energy is conserved. The final energy, including any change in thermal energy, equals the initial energy. the sum of the kinetic and potential energies mechanical energy The mechanical energy is conserved for an isolated system without ___________. friction a collision in which mechanical energy is conserved perfectly elastic collision the rate at which energy is transformed or at which work is done power The ________ an object, the more thermal energy it has. hotter the process of changing one form of energy to another energy transformations What is the general definition of efficiency? what you get / what you put in The larger the energy losses in a system, the lower its _____________. efficiency What are the units used for thermal energy? calories (cal) The thermal energy of an ideal gas is equal to the __________________ of the moving atoms in the gas. total kinetic energy The temperature of an ideal gas is a measure of the ___________________ of the atoms that make up the gas. average kinetic energy energy transferred between two objects because of a temperature difference between them heat the state of two or more objects or substances in thermal contact when they have reached a common temperature thermal equilibrium Two systems placed in thermal contact will transfer thermal energy from _______ to ______ until their final temperatures are the same. hot; cold For systems in which only the thermal energy changes, the change in thermal energy is equal to the energy transferred into or out of the system as work W, heat Q, or both. First law of thermodynamics the study of energy transformations thermodynamics an object or a part of the environment so large that, like the ocean, its temperature does not noticeably change when heat is transferred between the system and the reservoir energy reservoir Thermal energy is naturally transferred from a hot reservoir to a cold reservoir; it is possible to take some of this energy as it is transferred and convert it to other forms. This is the job of a device known as a ____________. heat engine does the job of transferring heat energy from a cold reservoir to a hot reservoir heat pump energy removed from the cold reservoir / work required to perform the transfer OR energy added to the hot reservoir / work required to perform the transfer coefficient of performance (COP) A ___________ coefficient of performance (COP) means a more efficient heat pump. larger The ______________ of thermodynamics limits the efficiency of a heat pump just as it limits the efficiency of a heat engine. second law The spontaneous transfer of heat from hot to cold is an example of an ______________ process, a process that can happen in only one direction. irreversible a process that can happen in only one direction irreversible a measure of the disorder of a system entropy The entropy of an isolated system never decreases. The entropy either increases, until the system reaches equilibrium, or, if the system began in equilibrium, stay the same. second law of thermodynamics When another form of energy is converted into thermal energy, there is an ___________ in entropy. increase True or False: No heat engine can be 100% efficient. true All temperatures in equations must be in __________. Kelvin (K)