When a bow is stretched it stores 10j and the arrows mass is 50g as it is projected show that the arrow has a speed of 20m/s
WITH FORMOULA

20 m/s

Explanation:

The stored energy is transformed to kinetic energy and since kinetic energy is given by

where m is the mass of arrow in Kg and v is the velocity of the arrow in m/s. From the principle of energy, all the energy is transformed to KE.

KE= Energy stored in bow

Changing mass from 50 g to Kg we divide by 1000 hence m=50/1000=0.05 Kg

Substituting 0.05 Kg for m and 10 J for KE then we have

0.5\times 0.05\times v^{2}=10 J

Making v the subject of the formula then

Therefore, the velocity is equivalent to 20 m/s

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle