7. Mechanical energy... [Choose all correct options. Multiple choices may be correct. Enter your answer as a string, so if you believe A, B, and D to be correct, enter 'ABD'.] A) is a new form of energy, different than kinetic or potential energy. B) increases when a system is deformed from its stable equilibrium. C) is kinetic energy plus potential energy. D) stays constant if the system is isolated and elastic. Answer: Submit All Answers 13. A pair of carts, both of mass 1.1 kg are initially at rest. Between them, a spring of stiffness 35 J/cm² is squeezed with s = -2 cm. When the system is released, the spring stretches back to its equilibrium length and the carts fly off in opposite directions. Use 'Before and After' analysis to find the speeds of the carts after they are pushed apart. Answer: Submit All Answers

1] A 20kg mass hangs at rest at end of a pendulum rope. Assume that you push it up at 0.6m above initial level and keep it there. Identify forces on the mass, use work- energy theorem in 3D and find: a) How much work do you spend for this operation... If it takes 0.6 sec to bring it from "A" to "B",... b) What average power you have exerted... c) How much work do you spend for this operation... If you keep it at rest at "B" for 2 minutes, Then, you leave free. •.. d) What is its speed when it arrives at A?... B 0.6m A

a.) A student is riding a bicycle at a constant speed of 6.0 m/s on a level road. The mass of the student and bicycle together is 80 kg. Assume the friction and drag is 35 N. What is the student's output power, in Watts?  b.) A student is riding a bicycle at a constant speed of 6.0 m/s on a 7.0º hill. The mass of the student and bicycle together is 80 kg. Assume the friction and drag is 35 N. What is the student's output power, in Watts?

Suppose the object starts from rest, the slide is frictionless and m = 3.50 kg. (Neglect air drag) A. What is the speed of the mass at point B? B. What is the speed of the mass at point C? C. The work done by gravity on the mass as it moves from A to C?

10. Jared and Clay are climbing the stairs. Jared gets tired and stops halfway to the fourth floor. Clay makes it to the fourth floor v.. a problem. If Jared is twice as heavy as Clay, who has more potential energy? Explain.

A car engine produces a constant power of P = 341 hp. The car and motor have a combined mass of m = 1830 kg. 1.) The car starts from rest, after t=5 seconds, what is the cars speed, you may assume no energy is required to spin the tires. 2.) Assume a dragster of mass m=1000kg can accelerate to cover  450 m and accelerate in 7.2 s from a dead stop, how much horsepower is the engine producing, assuming acceleration is constant?

3. An 80.0 kg student running at 3.5 m/s JUMPS up 2m into the air and grabs a rope that is hanging vertically up 2m from the ground. (ignore his height and assume his center of gravity is where he is holding the rope). How high from the ground will the student swing? SOLVE USING ENERGY PLEASE! Assume no air resistance. 2.0 m

2. Mikey sees that the right front tire (m 30.0 kg) of Granny's car has landed in front of him. He picks it up and runs for 40 m at a constant velocity of 2.0 m/s to return it to her. How much work did Mikey do on the tire from 10 m to 20 m into his run? =

1. A roller-coaster car with a mass of 1200 kg starts at rest from a point 20 m above the ground. At point B, it is 9 m above the ground. [Express your answers in kilojoules (kJ).] a. What is the initial potential energy of the car? b. What is the potential energy at point B? c. If the initial kinetic energy was zero and the work done against friction between the starting point and point B is 40 000 J (40 kJ), what is the kinetic energy of the car at point B 2. The time required for one complete cycle of a mass oscillating at the end of a spring is 0.80 s. What is the frequency of oscillation?

A 50 kg skier leaves the top of a 10 m high frictionless slope (point "a") from rest and reaches the bottom of the slope (point "") with a speed v,. He subsequently continues sliding on level ground to a full stop to a point "c" due to friction (i.e. 0.2 on the level ground). a. Write an expression for the total mechanical energy of the skier at point "a". b. Write an expression for the total mechanical energy of the skier at point "b". c. Use the Work-Energy Theorem to determine the work done from point “b" to point “c".