initial height of the pole vaulter = 4.2 m
height of the pole vaulter just before it touch the pad = 80 cm
so the total displacement of pole vaulter just before he will touch the pad = 4.2 - 0.80 = 3.4 m
now by kinematics
now after this he will come to rest after compressing the pad by 50 cm
so again we can use kinematics to find its acceleration
so here its acceleration will be - 66.64 m/s^2
Answer:
A meteor is B) an icy body with a long tail extending from it.
Explanation:
Meteors are very small dust particles that, when penetrating into the Earth's atmosphere, burn quickly by rubbing with the gases of the same. Some meteors, those with larger dimensions and appreciable weights, are brighter and can describe longer trajectories, showing longer.
In other words, the meteoroids, celestial bodies can vary in size between 100 micrometers up to 50 meters, they collide with the atmosphere of our planet and if the particles are of a small size, upon impact they enter combustion creating a flash, is what we know as meteor or shooting star. Therefore, the meteor is a luminous phenomenon that leaves behind a persistent trail.
So, <u><em>a meteor is B) an icy body with a long tail extending from it.</em></u>
Answer:
Displacement by cyclist is zero.
Explanation:
In the given question bicyclist is travelling in a rectangular track having P , Q and R edges.
The bicyclist starts from P and travel through Q and R and returned to P again.
We need to find its displacement.
We know displacement of a body is its difference between its initial position to final position.
Here in the given question the bicyclist returns to P again.
Therefore, total displacement by bicyclist is zero.
Hence, this is the required solution.
By definition, the refractive index is
n = c/v
where c = 3 x 10⁸ m/s, the speed of light in vacuum
v = the speed of light in the medium (the liquid).
The frequency of the light source is
f = (3 x 10⁸ m/s)/(495 x 10⁻⁹ m) = 6.0606 x 10¹⁴ Hz
Because the wavelength in the liquid is 434 nm = 434 x 10⁻⁹ m,
v = (6.0606 x 10¹⁴ 1/s)*(434 x 10⁻⁹ m) = 2.6303 x 10⁸ m/s
The refractive index is (3 x 10⁸)/(2.6303 x 10⁸) = 1.1406
Answer: a. 1.14
