A block of mass 2.50 kg is pushed 2.20 m
along a frictionless horizontal table by a
constant 16.0-N force directed 25.0 below
the horizontal.
Determine the work done on the block by
(a)the applied force,
(b)(b) the normal force exerted by the table,
and
(c)(c) the gravitational force.
(d) (d) Determine the total work done on the
block.
The force acting on a particle varies . Find the work
done by the force on the particle as it moves (a) from
x = 0 to x = 8.00 m, (b) from x = 8.00 m to x = 10.0 m,
and (c) from x = 0 to x = 10.0 m
A 0.600-kg particle has a speed of 2.00 m/s at
point A and kinetic energy of 7.50 J at point B.
What is
(a) its kinetic energy at A?
(b) (b) its speed at B?
(c) (c) the total work done on the particle as it
moves from A to B?
The electric motor of a model train accelerates the train
from rest to 0.620 m/s in 21.0 ms. The total mass of the
train is 875 g. Find the average power delivered to the
train during the acceleration.
True or false:
(a) If the net or total work done on a particle
was not zero, then its speed must have
changed.
(b) If the net or total work done on a particle
was not zero, then its velocity must have
changed.
(c) If the net or total work done on a particle was not zero, then its direction
of motion could not have changed.
(d) No work is done by the forces acting on a particle if it remains at rest.
(e) A force that is always perpendicular to the velocity of a particle never
does work on the particle.
Give an example of a particle that has constant
kinetic energy but is accelerating.
Can a non-accelerating particle have a changing
kinetic energy? If so, give an example.
True or false:
(a) The gravitational force cannot do work on an object,because it
is not a contact force.
(b) Static friction can never do work on an object.
(c) As a negatively charged electron is removed from a positively
charged nucleus, the force on the electron does work that as a
positive value.
d) If a particle is moving along a circular path, the total work being done on it is
necessarily zero.
By what factor does the kinetic energy of a particle change if its speed is doubled but
its mass is cut in half?