How does the cell allow small molecules to enter and exit

Block B has mass 4.00 kg and sits at rest on a horizontal, frictionless surface. Block A has mass 2.00 kg and sits at rest on top of block B. The coefficient of static friction between the two blocks is 0.400.

7. A stereo is able to convert 20% of its electrical energy into sound. If 1000 J of sound energy is produced, calculate the electrical energy used [Show all work]. 8. A vehicle is only 18% efficient. How was the other 82% of the energy lost?

A woman is sitting in her hotel room when there is a knock at the door. She opened the door to see a man whom she had never seen before. He said "oh I'm sorry, I have made a mistake, I thought this was my room.

Why should galaxy collisions have been more common in the past than they are today?

The following is an example of a physical or a chemical change? Alex made a beautiful origami swan out of a blue sheet of paper which she colored red.

Which of the following is considered a contact forces?1) the force between two magnets. 2) the gravitational pull of a planet. 3) friction between an object and air. 4) the force between two charged particles.

All matter can be described by using what properties

When a quantity of monatomic ideal gas expands at a constant pressure of 4.00*104pa, the volume of the gas increases from 2.00*10-3m3 to 8.00*10-3m3?

When the notebook is sitting on the table, what force prevents it from falling into the space below the table? If you don't know the name of this force, just describe it. What force keeps the notebook from floating in the air?

1. A moving object with a mass of 8.8 kg has linear momentum of magnitude 13 kg mis. What is the kinetic energy of the object? a) 19) b) 4.8 c) 9.63 d) 0.743 e) 38)