Answer:
Longitudinal Mechanical Wave
Explanation:
Mechanical waves are the waves that require medium to propagate. And a longitudinal wave is a wave in which the vibration of the energy(here: mass specifically) is in the direction of propagation of wave.
Shock wave, strong pressure wave in any elastic medium such as air, water, or a solid substance, produced by supersonic aircraft, explosions, lightning, or other phenomena that create violent changes in pressure.
Shock waves travel faster than sound and their speed increases as the amplitude of the wave is increased but their intensity fades faster due to the fact that some of its energy gets expended in the form of heat due to the resistance of the medium.
Work energy theorem states that net work done by forces on an object equals a change in kinetic energy
therefore
a) you push on a box and it moves
Answer:
Net external force acting on the rock when it is at the top of its trajectory is force due to gravity (mg).
Explanation:
The forces acting on a rock thrown up are force due to gravity and air resistance. Air resistance is directly proportional to velocity of rock, when velocity is zero air resistance is zero. When it is at the top of its trajectory its velocity is zero. So air resistance is also zero. Hence only gravitational force acts on the rock.
Net external force acting on the rock when it is at the top of its trajectory is force due to gravity (mg).