# If You Jump Barefoot on a Hard Surface, Your Legs Are Injured. but They Are Not Injured If You Jump on a Soft Surface like Sand Or Pillow. Why? - Physics

Short Note

If you jump barefoot on a hard surface, your legs are injured. But they are not injured if you jump on a soft surface like sand or pillow. Why?

#### Solution

In both the cases, change in momentum is same but the time interval during which momentum changes to zero is less in the first case. So, by "F"="dp"/"dt", force in the first case will be more. That's why we are injured when we jump barefoot on a hard surface.

Concept: Newton's First Law of Motion
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 5 Newton's Laws of Motion
Short Answers | Q 11 | Page 77