Question

force of the friction of stairs is large why ?​

Answer 1

Answer:

A stair climbing experiment was performed using a four-stair instrumented stairway. A force platform was mounted in the first stair. Four floor surfaces, including the original force platform surface and three additional floor coverings on the platform, were tested. Human subjects wore the same type of lab shoes and ascended and descended the stairway. Their ground reaction forces were collected. The results showed that when descending, the double-stair condition resulted in significant (p < .0001) higher vertical ground reaction force at foot landing as compared to the single-stair condition. 

Answer 2

Answer:

A force platform was mounted in the first stair. Four floor surfaces, including the original force platform surface and three additional floor coverings on the platform, were tested. Human subjects wore the same type of lab shoes and ascended and descended the stairway. Their ground reaction forces were collected. The results showed that when descending, the double-stair condition resulted in significant (p < .0001) higher vertical ground reaction force.

Explanation: