Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:

where
F is the force applied
is the change in momentum
is the time interval
The change in momentum can be written as

where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as

In this problem:
m = 5 kg is the mass of the fist
u = 9 m/s is the initial velocity
v = 0 is the final velocity
F = -45,000 N is the force applied (negative because its direction is opposite to the motion)
Therefore, we can re-arrange the equation to solve for the time:

Answer:
2.8 m 7.4 m/s
Explanation:
write all the values then use the equations of motion to find the distance and speed. please see attached photo
Answer:
a.14 s
b.70 s
Explanation:
a.Let the sidewalk moving in positive x- direction.
Speed of sidewalk relative to ground=
Speed of women relative to sidewalk=v=1.5m/s
The speed of women relative to the ground

Distance=35 m
Time=
Using the formula
Time taken by women to reach the opposite end if she walks in the same direction the sidewalk is moving=
b.If she gets on at the end opposite the end in part (a)
Then, we take displacement negative.
Speed of sidewalk relative to ground=
Speed of women relative to sidewalk=v=-1.5 m/s
The speed of women relative to the ground=
Time=
Hence, the women takes 70 s to reach the opposite end if she walks in the opposite direction the sidewalk is moving.
We need to consider no change in the temperature of gas (isothermal transformation)
Volume and pressure are inversely proportional magnitudes, so we can write: