Question

A small block on a frictionless, horizontal surface has a mass
of 2.50×10^{−2} kg . It is attached to a massless cord
passing through a hole in the surface (Figure 1) .The block is
originally revolving at a distance of 0.300 mfrom the hole with an
angular speed of 2.99 rad/s . The cord is then pulled from below,
shortening the radius of the circle in which the block revolves to
0.150 m. Model the block as a particle.

-Find the change in the Kinetic Energy of the block

Answer #1

given

mass of 2.50 X 10^{−2} kg

distance of 0.300 m

angular speed of 2.99 rad/s

radius of the circle in which the block revolves to 0.150 m

the kinetic energy

K_{1} = 0.5 I _{1}^{2}

= 0.5 X m X r_{1}^{2} X _{1}^{2}

= 0.5 X 0.025 X 0.3^{2} X 2.99^{2}

K_{1} = 0.010057 J

_{2} = (
0.3 / 0.15 ) X 2.99

_{2} =
5.98 rad/sec

K2 = 0.5 I _{2}^{2}

= 0.5 X m X r_{2}^{2} X _{2}^{2}

= 0.5 X 0.025 X 0.15^{2} X 5.98^{2}

K_{2} = 0.010057 J

the change in the Kinetic Energy of the block is = 0.010057 - 0.010057

**the change in the Kinetic Energy of the block is
zero**

A small block on a frictionless, horizontal surface has a mass
of 2.50×10−2 kg . It is attached to a massless cord passing through
a hole in the surface (Figure 1) . The block is originally
revolving at a distance of 0.300 m from the hole with an angular
speed of 2.33 rad/s . The cord is then pulled from below,
shortening the radius of the circle in which the block revolves to
0.150 m. Model the block as a...

A small block on a frictionless, horizontal surface has a mass
of 2.90×10−2 kg . It is attached to a massless cord passing through
a hole in the surface (Figure 1). The block is originally revolving
at a distance of 0.300 m from the hole with an angular speed of
2.53 rad/s . The cord is then pulled from below, shortening the
radius of the circle in which the block revolves to 0.150 m. Model
the block as a particle....

A small block on a frictionless, horizontal surface has a mass
of 2.70×10−2 kg . It is attached to a massless cord
passing through a hole in the surface (Figure 1). The block is
originally revolving at a distance of 0.300 m from the hole with an
angular speed of 2.33 rad/s . The cord is then pulled from below,
shortening the radius of the circle in which the block revolves to
0.150 m. Model the block as a particle....

A small block on a frictionless horizontal surface has a mass of
2.50

A wooden block of mass Mresting on a frictionless horizontal
surface is attached to a rigid rod of length land of negligible
mass, as shown in the figure to the right.The rod is pivoted at the
other end. A bullet of mass mtraveling parallel to the horizontal
surface and normal to the rod with speed vhits the block and
becomes embedded in it.(a)What is the linear momentum of the
bullet-block system?(b)What is the angular momentum of the
bullet-block system?(c)Is the...

A wheel (disk) of radius 0.2 m and mass 1 kg are mounted on a
frictionless horizontal axis. A massless cord is wrapped around the
wheel and attached to a 2 kg object that slides on a frictionless
surface inclined at an angle of 60 degrees with the horizontal.
What is the acceleration of the block as well as the angular
acceleration of the wheel about its axis of rotation?
Answer: 6.93 m/s^2, 34.64 rad/s^2

7) A block of mass m1 = 38 kg on a
horizontal surface is connected to a mass m2 =
21.6 kg that hangs vertically as shown in the figure below. The two
blocks are connected by a string of negligible mass passing over a
frictionless pulley. The coefficient of kinetic friction between
m1 and the horizontal surface is 0.24.
(a) What is the magnitude of the acceleration (in
m/s2) of the hanging mass?
Answer: m/s2
(b) Determine the...

1. Consider the diatomic nitrogen molecule N2, which is rotating
in the xy plane about the z axis passing through its center,
perpendicular to its length. The mass of each nitrogen atom is
about m= 2.40×10-26 kg, and at room temperature, the separation
between the two-nitrogen atom is d = 1.32×10-10 m. A typical speed
of a molecule is 4.60×1012 rad/s. If the nitrogen molecule is
rotating with this angular speed about the z axis, what is its
rotational kinetic...

A block rests on a frictionless horizontal surface and is
attached to a spring. When set into simple harmonic motion, the
block oscillates back and forth with an angular frequency of 8.9
rad/s. The drawing shows the position of the block when the spring
is unstrained. This position is labeled ''x = 0 m.'' The drawing
also shows a small bottle located 0.080 m to the right of this
position. The block is pulled to the right, stretching the spring...

A block rests on a horizontal, frictionless surface. A string is
attached to the block, and is pulled with a force of 48.0 N at an
angle θ above the horizontal. After the block is pulled through a
distance of 16.0 m its speed is v = 2.10 m/s, and 40.0 J
of work has been done on it.What is the mass of the block? (Answer
in kg)

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 5 minutes ago

asked 5 minutes ago

asked 5 minutes ago

asked 13 minutes ago

asked 30 minutes ago

asked 30 minutes ago

asked 35 minutes ago

asked 57 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago