Unit 4 Physics Test Review

Fluid Dynamics and Pressure

• Area and pressure are inversely proportional: as the nozzle area decreases, the pressure increases.
• Density increases when more mass occupies the same volume of space.
• Squeezing water increases pressure, forcing more water into a diver and increasing its density until it sinks.

Energy Transfers and Transformations

• Mechanical kinetic energy is transferred from the hammer to the mole.
• Chemical potential energy in a battery is transformed into light energy.
• To increase potential energy in a roller coaster, increase the height of the first hill.

Mathematical Equations and calculations

• Work ($W = F imes d$): $900\,N \times 50\,m = 45000\,J$
• Power ($P = \frac{W}{t}$): $\frac{60\,J}{30\,s} = 2\,W$
• Gravitational Potential Energy ($GPE = m \times g \times h$): $4400\,kg \times 9.8\,m/s^2 \times 28\,m = 1207360\,J$
• Kinetic Energy ($KE = \frac{1}{2}mv^2$): $\frac{1}{2} \times 500\,kg \times (2.3\,m/s)^2 = 1322.5\,J$
• Reference values: Area of $0.05\,m^2$

Kinetic Energy and Lift Factors

• Velocity has the greatest impact on kinetic energy because the value for velocity is squared while mass is divided in half; $ext{2 is more than 1/2}$.
• Objects with identical mass require different velocities to possess different amounts of kinetic energy.
• Methods to increase lift on a plane:   1. Bigger wing   2. Faster plane (stronger engines)