Awoman is reported to have fallen 161 ft from a building, landing on a metal ventilator box, which she crushed to a depth of 29 in. she suffered only minor injuries. ignoring air resistance, calculate: (a) the speed of the woman just before she collided with the ventilator and (b) her average acceleration while in contact with the box. (c) modeling her acceleration as constant, calculate the time interval it took to crush the box.

a) 31.02 m/s

b) - 653.24 m/s²

c) 50 ms

Explanation:

a) For a vertical movement, let's suppose that the woman fell by the rest, thus she's initial velocity v0 = 0 m/s. If she makes a distance (S) of 161 ft = 49.1 m, thus, her final velocity at the box, v is:

v² = v0² +2aS

The acceleration is the gravity acceleration, 9.8 m/s².

v² = 2*9.8*49.1

v² = 962.36

v =√962.36

v = 31.02 m/s

b) She crushes the box until she stops, so her final velocity will be 0 m/s. The initial velocity is now 31.02 m/s, and S = 29 in = 0.7366 m

0 = 31.02² + 2a*0.7366

-1.4732a = 962.36

a = - 653.24 m/s² (the negative signal indicates that she's dessacelaranting)

c) The time can be calculate by:

v = v0 + at

0 = 31.02 -653.24*t

653.24t = 31.02

t = 0.05 s = 50 ms

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.