Physics Work and Energy Concepts

<p>Sound energy</p> Signup and view all the answers

<p>661.5 J</p> Signup and view all the answers

<p>Food before digestion</p> Signup and view all the answers

<p>In collisions where heat is produced</p> Signup and view all the answers

<p>Energy changes from one form to another</p> Signup and view all the answers

<p>It is 4.13 MJ</p> Signup and view all the answers

<p>Watt</p> Signup and view all the answers

<p>How effectively it converts energy</p> Signup and view all the answers

<p>W</p> Signup and view all the answers

<p>9 J</p> Signup and view all the answers

<p>46 cm</p> Signup and view all the answers

<p>0.145 m</p> Signup and view all the answers

<p>1.69 m/s</p> Signup and view all the answers

<p>KE = 1/2 mv^2</p> Signup and view all the answers

<p>Power is the work done divided by time</p> Signup and view all the answers

<p>Principle of Conservation of Energy</p> Signup and view all the answers

<p>Kinetic energy increases with both the mass of the object and the square of its velocity.</p> Signup and view all the answers

<p>Kinetic energy is the energy of motion, while potential energy is the energy stored due to an object's position or condition.</p> Signup and view all the answers

<p>During a collision, momentum is conserved, but energy may be converted to other forms such as heat and sound, leading to losses.</p> Signup and view all the answers

<p>It means that energy can change forms, such as from kinetic to potential, but the total energy in a closed system remains constant.</p> Signup and view all the answers

<p>The kinetic energy is $100,000$ J, calculated using the formula $EK = \frac{1}{2}mv^2$.</p> Signup and view all the answers

<p>The gain in potential energy is $1471.5$ J, calculated using $EP = mgh$ with $g = 9.81$ m/s².</p> Signup and view all the answers

<p>Thermal energy is related to the kinetic energy of particles in a substance, while chemical energy is stored in the bonds of molecules.</p> Signup and view all the answers

<p>Work is defined as the product of force and the displacement in the direction of the force, measured in joules.</p> Signup and view all the answers

<p>If the speed is doubled, the kinetic energy increases by a factor of four due to the square of the velocity.</p> Signup and view all the answers

<p>Sound energy is produced by the vibration of particles in a medium, while light energy is emitted as electromagnetic waves due to the motion of charged particles.</p> Signup and view all the answers

<p>Kinetic energy is transformed into potential energy as Amy ascends.</p> Signup and view all the answers

<p>The angle determines the height; a higher angle results in greater potential energy due to increased height.</p> Signup and view all the answers

<p>Gravity is the force that pulls both children back down, converting potential energy back into kinetic energy.</p> Signup and view all the answers

<p>Using standard units ensures that calculations are consistent and results are accurate.</p> Signup and view all the answers

<p>Use the equation $mgh = \frac{1}{2} mv^2$ to find height, leading to $h = \frac{v^2}{2g}$.</p> Signup and view all the answers

<p>Matthew's maximum speed indicates the peak kinetic energy he achieves just before descending.</p> Signup and view all the answers

<p>Power is the rate at which work is done; in swings, greater power indicates faster changes in kinetic energy.</p> Signup and view all the answers

<p>Her velocity becomes zero at maximum height because all kinetic energy is transformed into potential energy.</p> Signup and view all the answers

<p>Consider the height achieved, maximum speed, and energy lost to friction or air resistance.</p> Signup and view all the answers

<p>We assume that there are no external forces like friction or air resistance acting on the swings.</p> Signup and view all the answers

<p>To determine the efficiency, compare the work done on each swing to the gravitational potential energy gained at their maximum heights. The efficiency can be calculated using the formula: Efficiency = (Useful work output / Total energy input) x 100%.</p> Signup and view all the answers

<p>As Amy swings down, potential energy is converted into kinetic energy, reaching maximum kinetic energy at the lowest point where her velocity is highest.</p> Signup and view all the answers

<p>If Amy's initial velocity increased to 6 m/s, her maximum height would increase, as potential energy at the maximum height depends on the initial kinetic energy, which is higher with increased velocity.</p> Signup and view all the answers

<p>Matthew's maximum speed is influenced by his initial height, the angle of release, and the conservation of energy; all these factors determine the amount of potential energy converted to kinetic energy.</p> Signup and view all the answers

<p>Friction would cause energy loss due to work done against it, decreasing the useful energy output and thus lowering the calculated efficiency of both swings.</p> Signup and view all the answers

<p>Kinetic energy increases with mass and the square of velocity, given by the formula $E_K = \frac{1}{2} mv^2$. Doubling the velocity increases kinetic energy by a factor of four.</p> Signup and view all the answers

<p>Potential energy is due to an object's position, like a raised weight, while kinetic energy is due to motion, like a moving car. For example, a high jumper's gain in potential energy when raising their center of gravity is different from their kinetic energy while running before the jump.</p> Signup and view all the answers

<p>During a collision, some energy is converted to other forms, such as heat and sound. This conversion means that while momentum is conserved, total mechanical energy might not be conserved due to losses.</p> Signup and view all the answers

<p>This principle, known as the law of conservation of energy, implies that energy can only change forms, which is essential in engineering and environmental science. For instance, in a roller coaster, potential energy transforms into kinetic energy and vice versa.</p> Signup and view all the answers

<p>Thermal energy is the total kinetic energy of particles in a substance, affecting temperature and heat transfer. Unlike kinetic or potential energy, thermal energy is specifically related to the microscopic motion of particles.</p> Signup and view all the answers