Definitions
The definition of Energy is:
The ability to do work or to cause change.
Renatta Gass is out with her friends. Misfortune occurs and Renatta and her friends find themselves getting a workout. They apply a cumulative force of 1080 N to push the car 218 m to the nearest fuel station. Determine the work done on the car.
235440 J
The Law of conservation of energy states that:
Energy cannot be created or destroyed. (aka the total energy at the start of a scenario and the end of a scenario will never change)
A 6 kg bowling ball is rolling toward the pins at 7 m/s. What is the kinetic energy of the bowling ball?
147 J
The definition of work is:
Force acting on an object in the direction that the object moves
A 11kg brick is dropped from a height of 10m. Calculate the work that has been done on the brick between the moment it is released and the moment when it hits the ground. Assume that air resistance can be neglected
1100 J
As a ball falls from up high down to the ground what happens to the energy of the ball?
The ball loses potential energy, gains kinetic energy. And the total energy of the system remains the same.
A cart is loaded with a brick and pulled at constant speed along an inclined plane to the height of a seat-top. If the mass of the loaded cart is 3.0 kg and the height of the seat top is 0.45 meters, then what is the potential energy of the loaded cart at the height of the seat-top?
13.5 J
Which type of energy has to do with height?
Gravitational Potential Energy
Lamar Gant, U.S. powerlifting star, became the first man to deadlift five times his own body weight in 1985. Deadlifting involves raising a loaded barbell from the floor to a position above the head with outstretched arms. Determine the work done by Lamar in deadlifting 300 kg to a height of 0.90 m above the ground
2700 J
A 2kg ball is dropped from a 3.6m high balcony. What is the velocity of the ball at the bottom of the balcony right before it hits the ground?
8.49 m/s
A 20 kg box is attached to a compressed spring that has a spring constant of 300 N/m. The spring is compressed 0.03m. What is the SPE of the spring?
0.135 J
The definition of Kinetic Energy is:
The energy that has to do with motion.
A spider monkey (mass 40 kg) is frolicking through the jungle at a speed of 3.0 m/s. All of a sudden, a jaguar appears and tries to eat the monkey. The monkey begins to run frantically—now he has a speed of 14.0 m/s. How much work does the monkey do to increase its speed?
3740 J
A rollercoaster cart with a total mass of 1,000kg is at the top of a hill moving at 2m/s. Assuming no friction and neglecting air resistance, what is the speed of the cart when it reaches the bottom of the hill, 30m below?
24.58 m/s
A spring has a spring constant of 256 N/m. How far must it be stretched to give it an elastic potential energy of 48 J?
0.61 m
What is Elastic Potential Energy?
Energy that has to do with the compression or stretch of a spring or elastic object.
While training for breeding season, a 3.8kg male squirrel does 32 pushups in a minute, displacing its center of mass by a distance of 0.085m for each pushup. Determine the total work done on the squirrel while moving upward (32 times).
103.36 J
A rubber ball with m=15kg rolls down an incline with a height of 6.7m and an initial velocity of 2m/s. The ball rolls into a spring k=150N/m and compresses the spring. What distance (x) was the spring compressed?
3.71 m/s
An object has a kinetic energy of 25 J and a mass of 34 kg , how fast is the object moving?
1.21 m/s