Weight = (mass) x (gravity)
On Earth ...
Weight = (1 kg) x (9.8 m/s^2)
Weight = 9.8 Newtons
Answer:
x=22.33m
Explanation:
Kinematics equation for constant deceleration:

Gravitational potential energy = mgh or mass times acceleration due to gravity times the height
Here the mass is 0.25kg, the height is 10m, and gravity is 9.8m/s^2 so...
GPE = (0.25)(10)(9.8)
GPE = 24.5 J
m=23.8kg a=8.97m/s^2 Fnet=? Fnet=ma=(23.8kg)(8.97m/s^2)=213.486N