CBA #4

Look at the picture. The cart is moved from Point X to Point Y. Based on the information in the picture, the only quantity that can be calculated is:

• the cart’s final momentum.

• the work done in moving the cart.

• the amount of power applied to the cart.

• the cart’s velocity when it reaches Point Y.

Jon had a flat tire on his car. He used a hydraulic jack to lift the car up so that he could change the tire. If Jon knows the amount of force used to lift the car 0.25 meter off of the ground, what is he able to calculate?

• momentum

• power

• pressure

• work

The wheelbarrow is classified as a second-class lever. If a 500 N bag of soil is added to the wheelbarrow, which statement BEST describes the effort force?

• The effort equals load.

• The effort is less than load.

• The effort is greater than the load.

• The effort decreases mechanical advantage.

Peter does 3,000 joules (J) of work by moving an object 40 meters (m). What is the force that Peter applies to the object?

• 75 N

• 2,960 N

• 3,040 N

• 120,000 N

A robotic arm lifts a stack of cafeteria trays weighing 62 newtons (N). It moves the trays 2 meters (m). How much work has the robotic arm performed?

• 31 joules

• 64 joules

• 124 joules

• 186 joules

Neil studied how a pulley helps move an object. Neil tied a rope to an object with a mass of 10 kilograms (kg) and attached it to a pulley. He then pulled down on the rope. When Neil pulled down on the rope, which did he MOST likely learn about the force required to lift the object?

• It was half of the weight of the object.

• It was equal to the weight of the object.

• It was two times the weight of the object.

• It was three times the weight of the object.

Which property is changed between 100 mL of water at 5°C and 100 mL of water at 45°C?

• molecular mass

• atomic diameter

• bond length

• molecular motion

Which of the following BEST describes what a thermometer measures?

• amount of heat energy contained in a substance

• average kinetic energy of a substance’s molecules

• rate of flow of heat from a substance to the environment

• the melting point and boiling point of a substance

The average kinetic energy of particles in Object R is greater than the average kinetic energy of particles in Object S. Which statement describes what will MOST likely happen when Object R comes in contact with Object S?

• Energy will transfer from Object R to Object S.

• Energy will transfer from Object S to Object R.

• Molecules of Object R will have zero kinetic energy.

• Molecules of Object S will vibrate less than in Object R.

An iron sample heated to 90°C is immersed in water at 22°C. Which statement describes what happens to the molecular motion of the substances?

• Water molecules will move slower as heat energy flows from the iron to the water.

• Water molecules will move faster as heat energy flows from the iron to the water.

• Water molecules will move slower as heat energy flows from the water to the iron.

• Water molecules will move faster as heat energy flows from the water to the iron.