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Questions and Answers
A ball with a mass of 0.5 kg is thrown upwards with an initial velocity of 20 m/s. Neglecting air resistance, what is the kinetic energy of the ball at the instant it is thrown?
A ball with a mass of 0.5 kg is thrown upwards with an initial velocity of 20 m/s. Neglecting air resistance, what is the kinetic energy of the ball at the instant it is thrown?
- 10 J
- 25 J
- 200 J
- 100 J (correct)
A car of mass 1000 kg accelerates uniformly from rest to a velocity of 15 m/s in 5 seconds. What is the average power delivered by the engine during this acceleration?
A car of mass 1000 kg accelerates uniformly from rest to a velocity of 15 m/s in 5 seconds. What is the average power delivered by the engine during this acceleration?
- 30 kW
- 112.5 kW
- 22.5 kW (correct)
- 45 kW
A spring with a spring constant $k = 200 N/m$ is compressed by 0.2 m. What is the potential energy stored in the spring?
A spring with a spring constant $k = 200 N/m$ is compressed by 0.2 m. What is the potential energy stored in the spring?
- 4 J (correct)
- 40 J
- 8 J
- 16 J
A 2 kg block slides down a frictionless incline of height 5 m. What is the velocity of the block at the bottom of the incline?
A 2 kg block slides down a frictionless incline of height 5 m. What is the velocity of the block at the bottom of the incline?
A 0.1 kg dart is fired horizontally at a stationary 0.9 kg wooden block resting on a frictionless surface. The dart embeds itself in the block, and the combined mass moves off at a speed of 5 m/s. What was the initial speed of the dart?
A 0.1 kg dart is fired horizontally at a stationary 0.9 kg wooden block resting on a frictionless surface. The dart embeds itself in the block, and the combined mass moves off at a speed of 5 m/s. What was the initial speed of the dart?
A 2 kg object is lifted 3 meters vertically in 2 seconds. What is the power required to lift the object?
A 2 kg object is lifted 3 meters vertically in 2 seconds. What is the power required to lift the object?
A 5 kg bowling ball is rolling down the alley at 3 m/s. It strikes a stationary pin and, after the collision, the bowling ball's speed is reduced to 2 m/s. What is the change in kinetic energy of the bowling ball?
A 5 kg bowling ball is rolling down the alley at 3 m/s. It strikes a stationary pin and, after the collision, the bowling ball's speed is reduced to 2 m/s. What is the change in kinetic energy of the bowling ball?
A cyclist is traveling at a constant speed of 10 m/s on a level road. If the total resistive force acting on the cyclist is 20 N, what is the power output of the cyclist?
A cyclist is traveling at a constant speed of 10 m/s on a level road. If the total resistive force acting on the cyclist is 20 N, what is the power output of the cyclist?
A crane lifts a 100 kg object to a height of 20 meters in 10 seconds. Assuming constant acceleration, what is the work done by the crane?
A crane lifts a 100 kg object to a height of 20 meters in 10 seconds. Assuming constant acceleration, what is the work done by the crane?
A simple pendulum with a length of 1 meter is released from an angle of 30 degrees with the vertical. What is the approximate velocity of the pendulum bob at the lowest point of its swing?
A simple pendulum with a length of 1 meter is released from an angle of 30 degrees with the vertical. What is the approximate velocity of the pendulum bob at the lowest point of its swing?
Flashcards
Kinetic Energy
Kinetic Energy
Energy possessed by an object due to its motion.
Kinetic Energy Formula
Kinetic Energy Formula
Kinetic Energy = 0.5 * mass * velocity^2, measured in Joules.
Units for Kinetic Energy
Units for Kinetic Energy
Mass in kilograms (kg) and Velocity in meters per second (m/s).
Calculating Kinetic Energy: Lacey's Example
Calculating Kinetic Energy: Lacey's Example
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Study Notes
- Kinetic energy is the energy of motion
- Kinetic Energy (KE) Formula: KE = 0.5 * m * v^2, where m is mass in kilograms (kg) and v is velocity in meters per second (m/s)
- In the example, Lacey's mass (m) is 54 kg and her velocity (v) is 2.5 m/s
- Substitute the known variables into the kinetic energy formula: KE = 0.5 * 54 kg * (2.5 m/s)^2
- Square the velocity: (2.5 m/s)^2 = 6.25 m^2/s^2
- Multiply: KE = 0.5 * 54 kg * 6.25 m^2/s^2
- Multiply: KE = 27 kg * 6.25 m^2/s^2
- Kinetic Energy: KE = 168.75 Joules (J)
- Therefore, Lacey's kinetic energy is 168.75 J
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