Answer:
at the speed of light (
)
Explanation:
The second postulate of the theory of the special relativity from Einstein states that:
"The speed of light in free space has the same value c in all inertial frames of reference, where "
This means that it doesn't matter if the observer is moving or not relative to the source of ligth: he will always observe light moving at the same speed, c.
In this problem, we have a starship emitting a laser beam (which is an electromagnetic wave, so it travels at the speed of light). The startship is moving relative to the Earth with a speed of 2.0*10^8 m/s: however, this is irrelevant for the exercise, because according to the postulate we mentioned above, an observer on Earth will observe the laser beam approaching Earth with a speed of .
Answer
given,
Mass of the runner, M = 70 Kg
speed of the runner on the second base = 4.35 m/s
speed at the base = 0 m/s
Acceleration due to gravity,g = 9.8 m/s²
a) magnitude of mechanical energy lost
Mechanical energy lost is equal top gain in kinetic energy
b) Work done = Force x displacement
W = F. x
F = μ mg
W = μ mg . x
Work done is equal to 662.29 J
using the coefficient of the friction,μ = 0.7
x = 1.38 m
Hence, the runner will slide to 1.38 m.
Answer:
The magnitude of electrostatic force on each charge is quarter of the magnitude of initial electrostatic force. ( ¹/₄ F)
Explanation:
The electrostatic force between two charges is given by Coulomb's law;
where;
Q₁ and Q₂ are the magnitude of the charges
r is the distance between the charges
k is Coulomb's constant
Since the charges are identical;
Q₁ = Q
Q₂ = Q
the electrostatic force experienced by each charge is given by;
When each of the spheres has lost half of its initial charge;
Q₁ = Q/2
Q₂ = Q/2
Therefore, the magnitude of electrostatic force on each charge is quarter of the magnitude of initial electrostatic force.
