Why is it more helpful to know a tornado’s velocity rather than its speed? Because velocity includes direction. If we know the tornados velocity we know where it is going and how fast so we can notify people in the tornado’s path to seek shelter.

6m/s2.

3m/s2.

Speed is a description of how fast an object moves; velocity is how fast and in what direction it moves. In physics, velocity is speed in a given direction. When we say a car travels at 60 km/h, we are specifying its speed.

Speed denotes only how fast an object is moving, whereas velocity describes both how fast and in which direction the object is moving. If a car is said to travel at 60 km/h, its speed has been specified.

A fire spreads by transferring heat energy in three ways: Radiation, Convection, and Conduction. Radiation refers to the emission of energy in rays or waves. Heat moves through space as energy waves. It is the type of heat one feels when sitting in front of a fireplace or around a campfire.

Thermal energy is moved from hot spots to cold spots by convection. As the two bodies are kept in vacuum and without contact, conduction and convection are not possible. So, the heat has travelled from one body to the other in the form of radiation. Thus, radiation (A) is the correct answer.

Gravity does not play any part in radiation and conduction because in both these processes heat is transferred without any motion of the medium particles. However, in convection heat is transmitted through the substance from one point to another due to the motion of the heated particles of the substance.

Heat transfer in fluids generally takes place via convection. Convection currents are set up in the fluid because the hotter part of the fluid is not as dense as the cooler part, so there is an upward buoyant force on the hotter fluid, making it rise while the cooler, denser, fluid sinks.