Question

You roll out of bed in the morning. Typically beds are 0.5 m off the ground. What is the magnitude of the average force you will experience once you hit the floor if the collision tales 0.1 seconds. You may assume a mass for the average person is 65kg. A. 6370 N B. 2035 N C. 1018 N D. 3185 N

Answer 1

Velocity when you hit the ground=(2gh)^0.5 where g is gravitational acceleration and h is initial height.

Here,h=0.5 m.

So,velocity=(2*9.8*0.5)^0.5=3.13 m/s.

Now,final velocity after collision=0 m/s.

So, magnitude of change in velocity=3.13 m/s.

Time=0.1 s.

So, average acceleration=(change in velocity)/time=3.13/0.1=31.3 m/s2.

Now,force=mass*acceleration=65*31.3=2034.5 N=2035 N approximately (option B)