Physics T 5

Which of the following explains the relationship between work and power when running or walking up a flight of stairs

Running requires the same amount of work, but more power than walking

In a physics investigation, students drop a steel ball with a mass of 0.567 grams from a fourth-story window into a large sand pit. The release point is 10.0 m above the ground. Assuming no air resistance, how much kinetic energy does the ball have when it is 3.00 m above the surface of the sand

0.0389 J

What is the kinetic energy of a 4 kg cart pushed at a rate of 0.5 m/s

0.5 J

What is the kinetic energy of a 0.500 kg toy car moving at a rate of 1.50 m/s

0.563 J

Four objects are moved along the x-axis by an applied force. The initial and final positions of the objects and the applied forces are given in the table below. Which choice correctly ranks the amount of work done on the objects from lowest to highest

1, 2, 4, 3

The amount of work performed when an airplane took off from sea level and climbed to an altitude of 830 m in 65 s was 7.6 x 10 to 7 J. How much power from the airplane's engine was required to produce this amount of work

1.2 x 10 to 6 W

A student moves a 1.50 kg book from a shelf 2.00 meters high to a shelf 1.20 meters high. What is the approximate magnitude of the change in the gravitational potential energy of the book

12.0 J

A 2.00 kg stone block gains 44.0 J of gravitational potential energy when it is moved up a ramp. What is the height of the ramp? Use g = 10.0 m/s2

2.20 m

A crane operator in a junkyard used an electromagnet to lift an 1800-kg pickup truck from the top of a 2-meter-tall junk pile to a height of 15 meters. How much work was done by the crane

2.3 x 10 to 5 J

A soup manufacturing company has built a new motor-powered mechanical arm system to supply an average force of 300 N to push cases of soup cans a distance of 11 meters in 15 seconds. What is the power output required by the motor

220 W

The graph below shows the displacement of an object as a constant force is applied. About how much work was done on the object

3.6 J

A weightlifter lifts a 10 newton (N) weight to a height of 3 meters (m). How much work was done to move the weight

30.0 N-m

One of the fastest elevators ever designed will be built in Shanghai Tower. The elevator will travel at an average speed of 18 m/s to lift passengers to the top of a 571 m tall structure. If the maximum combined load of the elevator and passengers is 1757 kg, what power must be delivered by the motor to lift the elevator at the average speed

310 kW

Cheetahs can accelerate from 0 to 96 km/h in 3.0 seconds. If the average mass of a cheetah is about 40.0 kg, what is the average power expended by the cheetah during such an acceleration

4.7 kW

In some manual mining operations, the end of a cart line has a bumper stop with a spring to absorb energy from a moving cart. The bumper stop at the end of a particular minecart rail line has a spring constant of 1.32 x 10 to 6 N/m. If the bumper stop is compressed 30.0 cm by a runaway empty minecart, how much work was done to compress the spring

59.4 kJ

A 600-newton person runs up a set of stairs that is 2.5 meters high in 2 seconds. How much power has the person generated

750 watts

A 60.0-kg skier starts from rest at a height of 10.0 m on a 50 degree inclined snow-covered slope. The coefficient of kinetic friction between her waxed skis and the snow is 0.050. If the skier goes straight down the slope, what is the speed of the skier when she reaches the bottom

9.2 m/s

In which scenario is the MOST power generated within the system

A 1.55-kg spring (with spring constant 12,000 N/m) is compressed from its equilibrium length by 5.0 cm in 0.35 seconds

Many roller coasters function by mechanically transporting the cars up a large incline. The cars then roll down and up a series of hills, turns, and spirals until the cars come to rest at the passenger loading station. At which point will the roller coaster have the greatest amount of gravitational potential energy

At the top of the highest point

A spring is suspended vertically from a support clamp, and a block is attached to the end of the spring. A student pulls the block-spring system 5 cm from its equilibrium length and lets go. How do the elastic potential energy and kinetic energy of this system compare during an oscillation

Elastic potential energy is maximized when the block is 5 from the equilibrium length while the kinetic energy is maximized when the block passes through the equilibrium position

Electric companies charge residents by the kilowatt-hour. The kilowatt-hour is a measure of what

Energy

A metal pot holding water is being warmed on an electric stove burner. Which of the following statements BEST explains how the first law of thermodynamics applies to the water in the pot

Energy of the water = energy from the burner - work done on surroundings

During a physics laboratory experiment, students drop a 255-g mass from a height of 10 meters. The mass falls through electronic photo gates and the students use the data to generate graphs of the kinetic energy vs. time and the potential energy vs. time. Which statement identifies the two graphs that are correctly drawn

Graph A shows Kinetic Energy vs. Time; Graph B shows Potential Energy vs. Time

A 0.1-kg mass is dropped from a height of 10 m. Which graph shows how the total energy (J) of the system changes with time (s) for this drop

Graph C (straight line going straight right)

While descending on a steep mountain road, a driver brakes frequently to control the speed of the car. Which statement describes how the car's energy at rest at the top of the mountain has transformed by the time it reaches the bottom

It has transformed into kinetic energy and heat

Joelle noticed that when she uses the brakes on her bicycle while she is traveling at a slow speed, she stops moving immediately. When she is riding much faster, it takes more time for the bike to come to a stop after she applies the brakes. What is the BEST explanation for this observation

Joelle and her bike have more kinetic energy at higher speeds

Bob kicked a soccer ball so that it went from rest to a velocity of v. Lucy kicked the same ball, and it accelerated from rest to a velocity of 2v. How did the energies transferred to the ball by the two kicks compare

Lucy's kick gave four times as much energy to the ball as Bob's kick

A book is raised above a table and has a potential energy of 800 joules (J). The potential energy in the book is converted to almost 800 J of kinetic energy as it is dropped. What happens to MOST of the energy from the book when it hits the table

Most of the energy is converted to sound and heat energy

When a golf ball is dropped into a tray of wet sand, it sinks into the sand and leaves an indentation. The table shows the depth of indentation in the sand when the same golf ball was dropped from various heights. Which of these is the BEST explanation for the recorded results

The kinetic energy of the ball increased as the speed of its fall increased

The table below lists the power ratings of several household devices, and how long members of your household operate them one day. Which device consumes the most energy

Toaster oven