Answer:
+12 m/s
Explanation:
The velocity of an object moving of accelerated motion is given by:

where
v0 is the initial velocity of the object
a is the acceleration
t is the time
In this problem, the rocket starts from rest, so
. The acceleration is
, so the velocity after
will be

F1 = G * m*m / [2r] ^2 = G * m^2 / 4r^2
Given the the mass is proportional to the volume and the volume is proportional to r^3, the mass of each big sphere is 3^3 = 27 times the mass of the small spheres. And the distance between the centers is 3r + 3r = 6r
F2 = G * [27m * 27m]/* [6r]^2 = G* 27^2 m^2 / 36r^2 = 81 G*m^2 / 4r^2 = 81*F1
Therefore, F2 = 81F1
Answer: option D) 81F1.
Answer:
Speed in meter/sec will be 32.1777 m /sec
Explanation:
We have given speed = 72.4 miles per hour
We have to convert this speed in meter per second
We know that 1 miles = 1.6 km
So 72.4 miles = 72.4×1.6= 115.84 km
We also know that 1 km = 1000 m
So 115.84 km 
We know that 1 hour = 60×60 = 3600 sec
So 
Answer:
118.166 volt
Explanation:
We have given number of turns N =345
Sides of the rectangular coils is 12 cm =0.12 m
So area A =0.12×0.12=0.0144 
Magnetic field B =0.45 T
Angular speed =505 rpm
Speed in rad/sec 
The emf is given by
For maximum emf sinwt =1
So 
Answer: B. water frozen in the cracks of a rock help to break down the rock because water expands when frozen, and physically forces the rock apart