Answer:
12.5 m/s
Explanation:
The motion of the hammer is a free fall motion, so a uniformly accelerated motion, therefore we can use the following suvat equation:

Where, taking downward as positive direction, we have:
s = 8 m is the displacement of the hammer
u = 0 is the initial velocity (it is dropped from rest)
v is the final velocity
is the acceleration of gravity
Solving the equation for v, we find the final velocity:

So, the final speed is 12.5 m/s.
Answer:
Explanation:
a )
change in the gravitational potential energy of the bear-Earth system during the slide = mgh
= 45 x 9.8 x 11
= 4851 J
b )
kinetic energy of bear just before hitting the ground
= 1/2 m v²
= .5 x 45 x 5.8²
= 756.9 J
c ) If the average frictional force that acts on the sliding bear be F
negative work done by friction
= F x 11 J
then ,
4851 J - F x 11 = 756.9 J
F x 11 = 4851 J - 756.9 J
= 4094.1 J
F = 4094.1 / 11
= 372.2 N
Answer:
C. Pressure gradient equals gas flow over resistance.
Explanation:
As we know that pressure gradient is the driving force for the gas to flow from one point to other point
And we know that the flow rate is directly proportional to the driving force and it inversely depends on the resistance to flow
so we can say
Flow Rate = 
Flow Rate = 
so we can say that correct statements are as below
A. Gas flow equals pressure gradient over resistance.
B. Resistance equals pressure gradient over gas flow.
D. The amount of gas flowing in and out of the alveoli is directly proportional to the difference in pressure or pressure gradient between the external atmosphere and the alveoli.