A block of mass 2.52 kg is kept at rest as it compresses a horizontal massless spring
(k 116 N/m) by 9.73 cm. As the block
is released, it travels 0.537 m on a rough
horizontal surface before stopping.
The acceleration of gravity is 9.8 m/s.
Calculate the coefficient of kinetic friction
between surface and block.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m