Answer:
180 Newton(N)
Explanation:
force =mass *acceleration
=60 * 3
=180 kgm/s^2
=180 N
<span>electromagnetic.........</span>
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

The height of the ball above the ground is 38.45 m
First we will calculate the velocity of the ball when it touch the ground by using first equation of motion
v=u+gt
v=0+9.81×2.8
v=27.468 m/s
now the height of the ground can be calculated by the formula
v=√2gh
27.468=√2×9.81×h
h=38.45 m