An object is thrown horizontally from the open
window of a building. If the initial speed of the
object is 20 m/s and it hits the ground 2.0 s later,
from what height was it thrown? (Neglect air
resistance and assume the ground is level.)
Initial vertical velocity = 0
formula: s = ut + (1/2)*g*t^2
s = 0 + 1/2*9.8*2^2
s = 9.8*2 = 19.6 m
Buoyant force = 15N (and it's less than weight)
When a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star.This explosion made waves in space which squeezed the cloud of gas & dust.
Answer:
(c) 6.91x10^14 Hz
Explanation:
Find the level energy of n=2 and n=5, using the formula:

where 


To jump from n=2 to n=5 the electron absorbs a photon with energy equal to
, using the next formula to find specific wavelength
to that energy

Where
is the speed of light (
) and
is Planck's constant (
). Solve for
:

The frequency of this wavelength is calculated with this formula:


It's easy to roll the the basket ball than bowling ball
It is because bowling ball is solid spherical ball which will have less moment of inertia
its moment of inertia is given as

While for the hollow ball like basketball we know that moment of inertia is given as

so here we can see for the same mass if we take basketball then its moment of inertia is more so it is easy to roll basket ball then to roll bowling ball.
So it is easy to roll basket ball then rolling ball