Science Practice Questions: Energy, Power, and Physics Calculations

What is the kinetic energy of a 1,000 kg car moving at 20 m/s? Kinetic Energy = (1/2) \* mass \* velocity² = (1/2) \* 1000 kg \* (20 m/s)² = 200,000 J Calculate the gravitational potential energy of a 300 N rock climber standing 100 m from the base of a rock wall. Potential Energy = weight \* hei...

What is the kinetic energy of a 1,000 kg car moving at 20 m/s? Kinetic Energy = (1/2) \* mass \* velocity² = (1/2) \* 1000 kg \* (20 m/s)² = 200,000 J Calculate the gravitational potential energy of a 300 N rock climber standing 100 m from the base of a rock wall. Potential Energy = weight \* height = 300 N \* 100 m = 30,000 J What is the power output of a stage manager raising a curtain by doing 5,976 J of work in 12 seconds? Power = Work / Time = 5,976 J / 12 s = 498 W A light bulb is on for 12 seconds, using 1,200 J of energy. What is its wattage? Power = Energy / Time = 1,200 J / 12 s = 100 W What is the work done when a 60 N force pushes a chair 5 m? Work = Force \* Distance = 60 N \* 5 m = 300 J Use Ohm's Law to find the voltage if the current is 2 A and resistance is 12 Ω. Voltage = Current \* Resistance = 2 A \* 12 Ω = 24 V How much power is supplied by a 12 V car battery using 700 A? Power = Voltage \* Current = 12 V \* 700 A = 8,400 W Calculate the density of a container filled with mercury if its mass is 4,810 g and volume is 355 mL. Density = Mass / Volume = 4810 g / 355 mL = 13.55 g/mL How much work is done pushing a car 20 m with a force of 300 N? Work = Force \* Distance = 300 N \* 20 m = 6,000 J Calculate the energy content of a peanut that releases 8,368 J of energy. Energy in Calories = Energy in Joules / 4,184 J = 8,368 J / 4,184 J = 2 Calories Determine the atomic mass of gallium, which is 60% Ga-69 and 40% Ga-71. Atomic Mass = (0.60 \* 69) + (0.40 \* 71) = 69.8 What is the potential energy of a book weighing 13 N at a height of 1.5 m? Potential Energy = Weight \* Height = 13 N \* 1.5 m = 19.5 J Find the resistance if a voltage of 300 V produces a current of 15 A. Resistance = Voltage / Current = 300 V / 15 A = 20 Ω What is the kinetic energy of a 2 kg object moving at 3 m/s? Kinetic Energy = (1/2) \* 2 kg \* (3 m/s)² = 9 J A 500 W heater is used for 2 hours. How much energy is consumed? Energy = Power \* Time = 500 W \* 2 h \* 3600 s/h = 3,600,000 J How much charge flows if a 2 A current runs for 10 seconds? Charge = Current \* Time = 2 A \* 10 s = 20 C Calculate the acceleration if a force of 10 N is applied to a 2 kg mass. Acceleration = Force / Mass = 10 N / 2 kg = 5 m/s² A car increases velocity from 10 m/s to 30 m/s in 5 seconds. What is its acceleration? Acceleration = (Final Velocity - Initial Velocity) / Time = (30 - 10) / 5 = 4 m/s²