Explanation:
1st.
potential energy = 16 j
acceleration d t gravity = 9.8 m/s²
mass = 7 kg
we know
pe = m×g×h
16 = 7 × 9.8 × h
16 = 68.6h
16/68.6 = h
h = 2.16
2nd :
ke = 316 j
s = 10
we have
ke = 0.5×m×s²
316 = 0.5 × m × 10²
316 = 0.5 × m × 100
316 = 50m
316/50 = m
6.32 = m
m = 6.32 kg
may be check it once cuz I'm also not perfect at numericals too . I'm just 14 yo girl lol.
hope this helps :)