The impulse (the variation of momentum of the ball) is related to the force applied by

where

is the variation of momentum, F is the intensity of the force and

is the time of application of the force.
Using F=1000 N and

, we can find the variation of momentum:

This

can be rewritten as

where

and

are the final and initial momentum. But the ball is initially at rest, so the initial momentum is zero, and

from which we find the final velocity of the ball:
Her mass stays the same and her weight changes
Answers:
a) 10 m
b) time=1.6 s, frquency=0.625 Hz
c) 6.25 m/s
Explanation:
a) If there is a crest at each dock and another three crests between the two docks, and the wavelength
is the distance between to crests; this means we have
in
:

Clearing
:


b) This part can be solved by a Rule of Three:
If 10 waves ---- 16 s
1 wave ----- 
Then:

This is the period of the wave
On the other hand, the frequency
of the wave has an inverse relation with its period
:


This is the frequency of the wave
c) The speed
of a wave is given by the following equation:


Finally:

Answer:
A) object moves 20 N [West] or -20 N [East]
B) object moves 6 N [South] or -6 N [North]
C) object moves 90 N [West] or -90 N [East]
D) object does not move and is at rest*
*Rest means 0
Why:
A)both forces from north and south that are pushing against the object neutralize each other. Assume that north is positive and south is negative: 20 [N] + (-20) [S] = 0
On West and east, you can see that west has a greater force. Assume that west is negative and east is positive: 50 [E] + (-70) [W] = -20 [E]
Answer:
The angle is 
Explanation:
From the question we are told that
The distance of the dartboard from the dart is 
The time taken is 
The horizontal component of the speed of the dart is mathematically represented as

where u is the the velocity at dart is lunched
so

substituting values

=> 
From projectile kinematics the time taken by the dart can be mathematically represented as

=> 


=> 
![\theta = tan^{-1} [0.277]](https://tex.z-dn.net/?f=%5Ctheta%20%20%3D%20%20tan%5E%7B-1%7D%20%5B0.277%5D)
