DESPERATEA rocket of mass 40 000 kg takes off and flies to a height of 2.5 km as its engines produce 500 000 N of thrust.
b The rocket engines switch off at 2.5 km and the rocket slows down as it moves up until it stops momentarily and then falls to the ground.
i Calculate the rocket’s energy when the rocket engines were switched off.
ii Calculate the speed of the rocket when the rocket engines were switched off.

i=1250000000Nm

ii=50000m/s

Explanation:

energy=force ×distance

500000N×(2.5×1000)m

=1250000000Nm

ii. Force=mass ×acceleration

500000N =40000kg ×a

500000 ÷40000=12.5a

s=1/2at^2

2500m=1/2×12.5×t^2

2500m=6.25×t^s

2500÷6.25=400

t^2=400

√t^2=√400

t=20seconds

speed=distance ×time taken

=2500m × 20s

=50000m/s

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