What principle explains why lifting heavy objects is easier using ramps?

Hot air balloon A is rising upward a rate of 5.0 m/s. A passenger aboard balloon A observes balloon B rising upward at a relative rate of 7.5 m/s. What is the velocity of balloon B relative to the ground? Assume that up is positive.

The enthalpy of fusion of ice is 330,000 J/kg. If I have a 1 kg sample, how much energy is needed to melt all of it? A. 33,000 J B. 3,300 J C. 330,000 J D. 330 J

A cat has a mass of 3 kg and runs at a speed of 6 m/s. how much KE does the cat have

In the middle of the Indian Ocean, the tsunami referred to in the passage was a train of pulses approximating a sinusoidal wave with speed 200 m/s and wavelength 150 km. What was the approximate period of these pulses? A. 1 min B. 3 min C. 5 min D.

A fallout shelter is a closed off building or teach designed to offer protection from radiation following a nuclear explosion. fallout shelter are constructed with very thick lead, concrete, or packed dirt walls.

Which drum would make a sound that fades away faster - one that makes a loud sound or one that makes a more mellow sound Why?

Which of the following is NOT a way to increase the solubility of a solid in water? A. crushing the solid B. shaking the mixture of solid and water C. raising the temperature of the water D. letting the mixture stand still a long time

Which of the following is true about cells? A. Cells have specialized components that perform different, specific functions. B. A cell's components are all identical and perform the same function. C.

How much heat is contained in 100 kg of water at 60.0 °C?

Which of the following statements is the best definition of weather? Weather is the current conditions in the atmosphere. Weather is the usual conditions in the atmosphere. Weather is the average conditions in the atmosphere.