Physics Chapter 5
Which of the following formulas would be used to directly calculate the kinetic energy of an object with mass m bouncing up and down on a spring with spring constant k?
KE= 1/2mv² you idiot
A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream cone? a. 0 J b. 0.5 J c. 2 d. 20 J
a
Which of the following refers to the sum of kinetic energy and all forms of potential energy? a. total energy b. Σ energy c. nonmechanical energy d. mechanical energy
a
Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present? a. Kinetic energy is not completely converted to a form of potential energy. b. Potential energy is completely converted to a form of gravitational energy. c. Chemical energy is not completely converted to electrical energy. d. Kinetic energy is completely converted to a form of gravitational energy.
a
A worker does 25 J of work lifting a bucket, then sets the bucket back down in the same place. What is the total net work done on the bucket? a. -25 J b. 0 J c. 25 J d. 50 J
b
Which of the following are not units of power? a. hp b. J c. W d. J/s
b
Friction converts kinetic energy to a. mechanical energy. b. potential energy. c. nonmechanical energy. d. total energy.
c
Which of the following are examples of conservable quantities? a. potential energy and length b. mechanical energy and length c. mechanical energy and mass d. kinetic energy and mass
c
Which of the following is a form of mechanical energy? a. internal energy b. chemical potential energy c. gravitational potential energy d. electrical energy
c
For which of the following situations is the conservation of mechanical energy most likely to be a valid assumption? a. A skateboard rolls across a sewer grate. b. A parachutist falls from a plane. c. You rub your hands together to keep warm. d. A soccer ball flies through the air.
d
In the presence of frictional force, a. nonmechanical energy is negligible and mechanical energy is no longer conserved. b. nonmechanical energy is negligible and mechanical energy is conserved. c. nonmechanical energy is no longer negligible and mechanical energy is conserved. d. nonmechanical energy is no longer negligible and mechanical energy is no longer conserved.
d
Which of the following is the rate at which energy is transferred? a. potential energy b. kinetic energy c. mechanical energy d. power
d
Which of the following is the rate at which work is done? a. potential energy b. kinetic energy c. mechanical energy d. power
d
If an object is moving in a horizontal direction, only the work done in the ____________ direction counts
horizontal So for something pushed, say, in a downward direction, the force in the y direction doesnt count as work
