Explanation:
Speed or velocity (V) = 35 m/s
Kinetic energy (K. E) = 1500 Joule
mass (m) = ?
We know
K.E = 1/2 * m * v²
1500 = 1/2 * m * 35²
1500 * 2 = 1225m
m = 3000 / 1225
m = 2.45 kg
The mass of the object is 2.45 kg
Hope it will help :)
1) Frequency: 
the energy of the photon absorbed must be equal to the ionization enegy of the atom, which is

The energy of a photon is given by

where
is the Planck's constant. By using the energy written above and by re-arranging thsi formula, we can calculate the frequency of the photon:

2) Wavelength: 91.2 nm
The wavelength of the photon can be found from its frequency, by using the following relationship:

where
is the speed of light and f is the frequency. Substituting the frequency, we find

A conservative force is a force that when work is done against this force the work done does not depend on the path taken only the initial and final position.
Hello Again! I think the Answer might be 220 m! ( 1/2) ( 21 m/s + 0 m/s) (21 s) = 220 m
Answer:
<em>TRUE</em>
Explanation:
The gravitational force between two objects becomes<u><em> weaker</em></u><em> if the two objects are </em><u><em>moved apart</em></u> and <em>stronger</em><em> if they are brought </em><em>closer</em><em> together</em>; that is, the force depends on the distance between the objects