Exam 7: Work and Kinetic Energy

An airplane flies 160 km at a constant altitude in a direction 30.0° north of east. A wind is blowing that results in a net horizontal force on the plane due to the air of 2.40 kN in a direction 10.0° south of west. How much work is done by the air on the plane?

How many joules of energy are used by a 2.0 hp motor that runs for 1.0 hr?

As compared to Jack, Jill does twice the work in half the time. Jill's power output is

If you walk 5.0 m horizontally forward at a constant velocity carrying a 10 N object, the amount of work you do is

What is the power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds?

If the net work done on an object is zero, then the object's kinetic energy

FIGURE 7-2 Three applied forces, F₁ = 20.0 N, F₂ = 40.0 N, and F₃ = 10.0 N act on an object with a mass of 2.00 kg which can move along an inclined plane as shown in the figure. The questions refer to the instant when the object has moved 0.600 m along the surface of the inclined plane in the upward direction. Neglect friction and use g = 10.0 m/s². -Refer to Figure 7-2. What is the amount of work done by force F₁ as the object moves up the inclined plane?

On a force vs. position graph, the area under curve is a representation of

A person carries a mass of 10 kg and walks along the +x-axis for a distance of 100 m with a constant velocity of 2 m/s. What is the work done by this person?

If the net work done on an object is negative, then the object's kinetic energy

Work done by STATIC FRICTION is always

If you push twice as hard against a stationary brick wall, the amount of work you do

FIGURE 7-4 A constant force of 100 N is applied to a mass of 40.0 kg as shown in Figure 7-4. The force causes a displacement of 20.0 m to this mass along the + x-axis. Neglect friction. -What is the work done by the component of the force in Figure 7-4 along the + y-axis?

The ratio of power outputs of Jack and Jill is 2: 1 to complete a certain amount of work. If Jill takes 4 minutes to complete this work, how long will Jack take to finish the same work?

A car accelerates from rest to a speed of 19.0 m/s in 6.00 seconds. If the car weighs 16,000 N, what average power must the motor produce to cause this acceleration? Use g = 10 m/s².

A student slides her 80.0-kg desk across the level floor of her dormitory room a distance 4.00 m at constant speed. If the coefficient of kinetic friction between the desk and the floor is 0.400, how much work did she do?

A 4.0 kg mass is moving with speed 2.0 m/s. A 1.0 kg mass is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

A 5.00-kg box slides 4.00 m across the floor before coming to rest. What is the coefficient of kinetic friction between the floor and the box if the box had an initial speed of 3.00 m/s?

FIGURE 7-1 -Which of the graphs in Figure 7-1 illustrates Hooke's Law?

FIGURE 7-5 -An object is under the influence of a force as represented by the force vs. position graph in Figure 7-5. What is the work done as the object moves from 0 m to 4 m?