![\vec F = I (\vec L \times \vec B)](https://tex.z-dn.net/?f=%20%5Cvec%20F%20%3D%20I%20%28%5Cvec%20L%20%5Ctimes%20%20%5Cvec%20B%29%20)
if currents go in opposite directions, wires repel
Answer:
V = f λ speed of wave in terms of frequency and wavelength
t = S / V time for wave to travel a distance S
t = 91.4 m / 344.5 m/s = .265 sec time to travel 91.4 m
Answer:Racquet force is twice of Player force
Explanation:
Given
ball arrives at a speed of ![u=-40\ m/s](https://tex.z-dn.net/?f=u%3D-40%5C%20m%2Fs)
ball returned with speed of ![v=40\ m/s](https://tex.z-dn.net/?f=v%3D40%5C%20m%2Fs%20)
average Force imparted by racquet on the ball is given by
![F_{racquet}=\frac{m(v-u)}{\Delta t}](https://tex.z-dn.net/?f=F_%7Bracquet%7D%3D%5Cfrac%7Bm%28v-u%29%7D%7B%5CDelta%20t%7D)
where ![m=mass\ of\ ball](https://tex.z-dn.net/?f=m%3Dmass%5C%20of%5C%20ball)
time of contact of ball with racquet
![F_{racquet}=\frac{m(40-(-40))}{\Delta t}](https://tex.z-dn.net/?f=F_%7Bracquet%7D%3D%5Cfrac%7Bm%2840-%28-40%29%29%7D%7B%5CDelta%20t%7D)
![F_{racquet}=\frac{80m}{\Delta t}-----1](https://tex.z-dn.net/?f=F_%7Bracquet%7D%3D%5Cfrac%7B80m%7D%7B%5CDelta%20t%7D-----1)
When it land on the player hand its final velocity becomes zero and time of contact is same as of racquet
![F_{player}=\frac{m(0-40)}{\Delta t}](https://tex.z-dn.net/?f=F_%7Bplayer%7D%3D%5Cfrac%7Bm%280-40%29%7D%7B%5CDelta%20t%7D)
![F_{player}=\frac{-40m}{\Delta t}-----2](https://tex.z-dn.net/?f=F_%7Bplayer%7D%3D%5Cfrac%7B-40m%7D%7B%5CDelta%20t%7D-----2)
From 1 and 2 we get
![F_{racquet}=-2F_{player}](https://tex.z-dn.net/?f=F_%7Bracquet%7D%3D-2F_%7Bplayer%7D)
Hence the magnitude of Force by racquet is twice the Force by player
Answer:
Momentum is 100 kg.m/s
Explanation:
given
mass, m = 5 kg
velocity, v = 20 m/s
To find : momentum (P)
We know that momentum is given by equation:
p = mv
= 5 kg x 20 m/s
= 100 kg.m/s