Ejercicios Resueltos de Physics & Chemistry (2º ESO)

An object of mass 2 kg is falling at 7 m/s. What is this object’s kinetic energy?

What mass of iron would need 1 450 cal of energy in order to raise its temperature by 19.7 ºC?

Define, in your own words, what energy is and write two examples of systems; one with kinetic energy and other with gravitational potential energy. Match the terms to these two groups (letter-number):

a) Combustion of diesel ; b) Friction between a match and sandpaper ; c) A bee flying ; d) A plane that took off a minute ago ; e) A pole when is completely bent.

1) Kinetic energy ; 2) Elastic potential energy ; 3) Mechanical energy ; 4) Chemical energy ; 5) Internal energy

The refractive index of green light in water is 1,42. What is its velocity when it travels through water?

(Velocity of light in a vacuum is 300 000 km/s).

A spring is producing waves of frequency 4 Hz and wavelength 0.5 m. What is its velocity? What will be its wavelength if the frequency is double? What will be its wavelength if frequency is reduced to half?

What is the physical magnitude of sound related with tone?

The wavelength of a wave is 0.00015 m and its frequency is 7 000 Hz. What is the velocity of the wave?

Is sound able to travel through a vacuum?

An electromagnetic wave is travelling through a vacuum. If its frequency is 1 MHz, what will be its wavelength?