How much work is done when a 4kg block of ice is moved from rest to a speed of 5m/s?   A. 50 J   B. 100 J   C. 20 J   D. 10 J

How much work (in J) must be done to lift a stack of bricks, which has a mass of 50 kg, from the ground to a height of 6 m? (g = 10 m/s?) A. 300J B. 500 J C. 3,000) D. 5,000J E. zero J

A cheetah can accelerate from rest to 7.4 m/s (about 18 m/h) in 1.8 seconds. How much average power does the cheetah generate during the acceleration phase of its motion if its mass is 51 kg?a) 1400 W. b) 1600 W. c) 1800 W. d) 2500 W. e) 2800 W.

You lift a box off the ground and then hold it at a height above your waist. Which does not describe the work or energy in this process? A. You did positive work on the box. B. Gravity did negative work on the box C. The box's gravitational potential energy increased. D. The box's kinetic energy remained constant throughout the process.

A cheetah can accelerate from rest to 7.4 m/s (about 17 m/h) in 1.1 seconds. How much average power does the cheetah generate during the acceleration phase of its motion if its mass is 51 kg? a) 1300 W. b) 1500 W. c) 1900 W. d) 2200 W. e) 2600 W.

Which of the following statements are TRUE? A. Energy is a vector physical quantity. B. Energy is always required to do work. C. Totol mechanical energy can never be zero. D. When law of conservation of mechanical energy is invoked, there can never be a waste energy in an ideal system. E. When law of conservation of mechanical energy is invoked, there can never be a waste energy in a real-world system. F. Kinetic energy can be negative. G. Potential energy can be negative. H. Work is equivalent to the negative change in kinetic energy. I. Work is equivalent to the negative change in potential energy. J. In a conservative system where only gravitational force acts, the total mechanical energy is constant at every point of the motion. K. In a non-conservative system where certain external forces may act, the total mechanical energy is not constant at every point of the motion. L The entire universe may be considered as a closed system where the total energy is constant. chnices O B. D.…

3. A 10-Newton object moves to the left at 1 m/s. Its kinetic energy is approximately ____ Joules if you double the speed. a. 0.5 b. 1 c. 10 d. 20  4. Which best describes potential energy? a. Energy as heat b. stored energy c. energy that is used to do work d. energy of motion.

A 20%-efficient car engine accelerates the 1500 kg car from rest to 20 m/s  How much energy is transferred to the engine by burning gasoline?

A body moves with increasing speed.  Which of the following statements is true? A. The net work done on the body is positive, and the kinetic energy is increasing. B. The net work done on the body is positive, and the kinetic energy is decreasing. C. The net work done on the body is zero, and the kinetic energy is decreasing. D. The net work done on the body is negative, and the kinetic energy is increasing. E. The net work done on the body is negative, and the kinetic energy is decreasing.

86. What is the kinetic energy of a 20kg object moving at 2 m/s? * O a. 10 J b. 20 J C. 40 J O d. 100 J