How do we determine the number of protons an element has

A motorist driving a 1000-kg car wishes to increase her speed from 20 m/s to 30 m/s in 5 s. Determine the horsepower required to accomplish this increase. Neglect friction.

How does a water dam increase the efficiency of a waterwheel

6. A Soldering Iron has a power of 25W. It uses the 230V mains supply. What is the current when it is switched on?

Explain why the inevitable conversion of energy to less useful forms should guide us to conserve energy resources and develop more renewable energy sources.

Which of the following is the most accurate statement concerning volume and pressure of a gas? Volume of a gas is equal to pressure of that gas in any container. Volume of a gas is always greater than pressure of that gas in any container.

Define colloid and list two examples.

An earthquake 50km from a city produces P and S waves that travel outward at 5000 and 3000 m/s, respectively. Once city residents feel the shaking of the P wave, how much time do they have before the S wave arrives?

You throw a rock upwards; it rises and then falls back down. We know that the acceleration due to gravity is 9.8 m/sec2 near the surface of earth.

Wich process occurs in a human muscle when it is forced to make tap without oxegen

What type of waves do you think sunscreen our skin from cancer from?