solution:
radius of steel ball(r)=5cm=0.05m
density of ball =8000kgm
terminal velocity(v)=25m/s^2
density of air( d) =1.29 kgm
now
volume of ball(V)=4/3pir^3=1.33×3.14×0.05^3=0.00052 m^3
density of ball= mass of ball/Volume of ball
or, 8000=m/0.00052
or, m=4.16 kg
weight of the ball (W)= mg=4.16×10=41.6 N
viscous force(F)=6 × pi × eta × r × v
=6×3.14×eta×0.05×25
=23.55×eta
To attain the terminal velocity,
Fiscous force=Weight
or, 23.55× eta = 41.6
or, eta = 1.76
whete eta is the coefficient of viscosity.
Answer:
The car must be moving away from the person.
Explanation:
From Doppler's Effect, we know that when a sound source moves towards a stationary observer, the apparent frequency of that sound increases. While the apparent frequency decreases if the source moves away from the stationary observer.
The audible range of frequencies for a human ear is 20 Hz to 20000 Hz. Therefore, in order for the sound of a loud speaker to be audible for the person, the frequency must decrease below 20000 Hz.
<u>Due to this reason, the car must be moving away from the person.</u>
Answer:
earth strong gravity
Explanation:
The only planet that have water bodies is earth. We know that water is one of the important factors for all living organism. Liquid water exists on the earth's surface is due to the atmospheric pressure. The reason behind this is not completely mentioned.
There are so many hypothesis about it. Out of given options the correct option is earth's strong gravity.
Hence, the correct option is (b) " earth strong gravity ".
<h2>
Option 3, 216 m is the correct answer.</h2>
Explanation:
We have initial velocity, u = 15 m/s
Time, t = 12 seconds
Final velocity, v = 21 m/s
We have equation of motion v = u + at
Substituting
21 = 15 + a x 12
a = 0.5 m/s²
Now we have equation of motion v² = u² + 2as
21² = 15² + 2 x 0.5 x s
s = 216 m
Displacement = 216 m
Option 3, 216 m is the correct answer.
Answer:
The value is 
Explanation:
From the question we are told that
The initial speed of the roller coaster is 
The length of the hill is 
The acceleration of the roller coaster is 
Generally the acceleration is mathematically represented as
Here 
is the initial time which is equal to zero
is the final velocity which is mathematically represented as
So
Solving this using quadratic formula we obtain
Generally time cannot be negative so
Generally the final velocity is mathematically represented as
