Physics Quiz 3

All objects, regardless of mass, will fall at the same rate. Heavier things have a greater gravitational force AND heavier things have a lower acceleration. It turns out that these two effects exactly cancel to make falling objects have the same acceleration regardless of mass.

When the ice was floating, the volume of water displaced had a mass equal to that of ice. After melting, that mass of ice has been converted into water. Therefore, there is no change in water level.

The Plimsoll line is a reference mark located on a ship's hull that indicates the maximum depth to which the vessel may be safely immersed when loaded with cargo.

Rocket engines and boosters carry both fuel and an oxidizer. For solid fuel, the components are aluminium and ammonium perchlorate. For liquid fuel, the components are liquid hydrogen and liquid oxygen. When combined, the fuels release water, which allows the rocket to leave the ground.

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. The frequency of ultrasound waves is above 20 kHz.

A barometer measures air pressure. A rising barometer indicates increas­ing air pressure and a falling barometer indicates decreasing air pressure. When atmospheric pressure drops suddenly, this usually indicates that a storm is on its way.

Remote-sensing device (RSD) has an inbuilt source of infrared Ray. Remote sensing is a type of geospatial technology that samples emitted and reflected electromagnetic (EM) radiation from the Earth's terrestrial, atmospheric, and aquatic ecosystems in order to detect and monitor the physical characteristics of an area without making physical contact.

The principle involved in a refrigerator is the rapid absorption of heat by the rapid evaporation of a volatile liquid. Refrigerators use a liquid that evaporates very easily, and this evaporation creates a cooling effect. They then compress the gas into a liquid again, and the whole process starts over.

The fuse breaks the circuit if a fault in an appliance causes too much current to flow. This protects the wiring and the appliance if something goes wrong. The fuse contains a piece of wire that melts easily.

Pure water is a bad conductor of electricity because it is feebly ionized. The presence of ions is necessary in order for any solution to conduct electricity. Pure water is free from any kind of acids, bases or salts. Hence, it does not conduct electricity due to the absence of ions.