Question

your feet will go deep in sand if you stand over it but you will not go that deep while lying down on it .​

Answer 1

Answer:

pressure = thrust÷surface area

thrust is your weight it will remain same while standing or lying but while lying you increase surface area decreasing the pressure applied on sand that's why you don't sink while lying

Answer 2

Answer:

because if stand over it,the weight of your body is concentrated at the feet,as a result you sink.But it is different in the case where you lie on it. When you lie down on it your weight is distributed equally over the body.So,you do not sink in the sand when you lay down on it