true or false: a image created by an object located inside the focal point is virtual, enlarged, and upright
True :D
Answer:
Explanation:
Given

angular velocity 
Combined moment of inertia of stool,student and bricks 
Now student pull off his hands so as to increase its speed to suppose
rev/s
After Pulling off hands so final moment of inertia is

Conserving angular momentum as no external torque is applied




Answer:
Check the explanation
Explanation:
The escape velocity is the velocity needed by any object to overcome the gravitational force of the planet on which it’s present. Now we know that the gravitational force is directly proportional to the mass of the planet and inversely proportional to the distance of the object from the center of planet.
If we keep the mass of earth constant and decrease the size of the earth than this will decrease the distance between the object and the center of the earth and thus the gravitational force that will act on the body will increase substantially which will in turn increase the value of the escape velocity.
The value of escape velocity will keep on increasing as the size of the earth will shrink till it reaches to a point when the value of escape velocity becomes more than the speed of light and since it’s impossible to travel with a speed greater than the speed of light and therefore at this point it will become impossible for a spacecraft to escape the earth.
Answer:
7.2 cm
Explanation:
magnetic field, B = 0.301 T
speed, v = 7.92 x 10^5 m/s
mass, m = 4.39 x 10^-27 kg
q = 1.6 x 10^-19 C
The radius of singly changed ion is given by

where, m is the mass of ion, v be the speed of ion, B is the magnetic field and q be the charge

r = 0.072 m
r = 7.2 cm