Please help, physics question:

A 0.155 kg arrow is shot upward at 31.4 m/s. What is its kinetic energy (KE) when it is 30.0 m above the ground?

thank you for your help in advance!

Kinetic energy (K.E) when it is 30.0 m above the ground is 30.84 J .

Explanation:

Given :

Mass of arrow , m = 0.155 kg .

Initial velocity , u = 31.4 m/s .

To Find :

Kinetic energy (K.E) when it is 30.0 m above the ground .

Solution :

Let , us assume upward direction be positive and downward direction is negative .

Now , by equation of motion :

Here , ( Because acceleration due to gravity is in downward direction )

Putting all given values in above equation , we get :

Now , kinetic energy is given by :

Putting all values we get :

K.E = 30.84 J .