Three masses are placed on the x-axis:
300 g at origin, 500 g at x= 40 cm and 400g
at x=70 cm. The distance of the center of
mass from the origin is
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Three masses are placed on the x-axis:
300 g at origin, 500 g at x= 40 cm and 400g
at x=70 cm. The distance of the center of
mass from the origin is
The instantaneous angular position of a point on
a rotating wheel is given by the equation
The torque on the wheel becomes zero at
According to question, torque,
It means that,
Given
so,
The moment of inertia of a thin uniform rod of
mass M and length L about an axis passing
through its mid-point and perpendicular to its
length is . Its moment of inertia about an
axis passing through one of its ends and
perpendicular to its length is
The theorem of parallel axis for moment of
inertia.
A body of mass M hits normally a rigid wall with velocity v and bounces back with the same velocity. The impulse experienced by the body is
Impulse
A mass m moving horizontally (along the x-axis) with velocity v collides and sticks to mass of 3m moving vertically upward (along the y-axis) with velocity 2v. The final velocity of the combination is
A circular disk of moment of inertia is rotating in a horizontal plane, about its symmetry axis, with a constant angular speed Another disk of moment of inertia is dropped coaxially onto the rotation disk. Initially the second disk has zero angular speed. Eventually both the disks rotate with a constant angular speed The energy lost by the initially rotating disc to friction is
Loss of energy,
=
A man of 50 kg mass is standing in a gravity free space at a height of 10m above the floor. He throws a stone of 0.5 kg mass downwards with a speed When the stone reaches the floor, the distance of the man above the floor will be
mr = constant
=
The distance of the man above the floor (total height)=10+0.1=10.1m.
An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, 1 kg first part moving with a velocity of and 2 kg second part moving with a velocity of If the third part flies off with a velocity of its mass would be
If is the force acting on a particle having position vector and be the torque of this force about the origin, then
Key Idea Torque is an axial vector ie, its direction is always perpendicular to the plane containing vectors and .
Torque is perpendicular to both and
∴
A thin circular ring of mass M and radius R is rotating in a horizontal plane about an axis vertical to its plane with a constant angular velocity If two objects each of mass m be attached gently to the opposite ends of a diameter of the ring, the ring will then rotate with an angular velocity -
Key Idea
Apply law of conservation of angular momentum.
In the given case
Then
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