Initial velocity (u) = 90km/hr = 90/3.6 m/s = 25m/s
final velocity (v) = 18km/hr = 18/3.6 m/s = 5m/s
acceleration = (v-u)/t = (5-25)/4 = -5 m/s2
change in momentum = m(v-u) = 1200(5-25) = -24000 kg•m/s
F = ma = 1200 x -5 = -6000 N
-- The total distance between the towns = 460 km.
-- For the first 3 hours, he travels at an average speed of 60 km/hr. During that time, he covers (60 km/hr) x (3 hrs) = 180 km.
-- At that point, he still has (460km - 180km) = 280 km to go.
-- If he drives that 280km at an average speed of 70 km/hr, it'll take him (280km)/(70km/hr) = 4 hrs to cover it.
-- His total time for the whole trip is (3 hours for the first part) + (4 hours for the last part) = <em>7 hours</em>.
Answer:
The relation between F1 and F2 is : F1 = - F2. That is the forces are equal in magnitude but opposite in direction.
Explanation:
- According to Newton's 3rd law of motion statement, it states that for all actions there is equal but opposite reaction.
- This law is also known as the law of symmetry. It means that forces occur in pairs in any conditions. An object will not apply force on other object without experiencing the force on itself.
- This means when an object exerts force F1 on another object, it also exerts the same force of same magnitude on itself in opposite direction to the force it exerted on another object.
The different types of radiation in electromagnetic spectrum are compared by the amount of energy found in the photons.
Radio waves have photons with low energies, microwave photons have a little more energy than radio-waves. Infrared photons still have more energy, then comes visible, ultraviolet, x-rays and the most energetic of all, gamma rays.
The energy associated with electromagnetic radiation is proportional to frequency and inversely proportional to wavelength. So, electromagnetic waves with shorter wavelengths have more energy.
On one end of the electromagnetic spectrum are radio waves, which have wavelengths billions of times longer than those of visible light. On the other end of the spectrum are gamma rays with wavelengths billions of times smaller than those of visible light.
To know more about electromagnetic spectrum:
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Answer:
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. ... For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes.