Advertisements
Advertisements
Question
A block of mass 1 kg is placed at point A of a rough track shown in figure following. If slightly pushed towards right, it stops at point B of the track. Calculate the work done by the frictional force on the block during its transit from A to B.
Advertisements
Solution
\[\text{ Given }, \]
\[\text{ Mass of the block, m = 1 kg }\]
\[\text{ Height of point A, H = 1 m }\]
\[\text{ Height of point B, h = 0 . 8 m }\]
Work done by friction = Change in potential energy of the body
\[\Rightarrow \text{W}_1 = \text{ mgh - mgH}\]
\[ = 1 \times 10 \left( 0 . 8 - 1 \right)\]
\[ = - 1 \times 10 \times \left( 0 . 2 \right) = - 2 \text{ J } \]
The work done by the frictional force on the block during its transit from A to B is - 2 joule.
APPEARS IN
RELATED QUESTIONS
A body constrained to move along the z-axis of a coordinate system is subject to a constant force F given by
`F = -hati+2hatj+3hatkN`
Where `hati,hatj,hatk` are unit vectors along the x-, y- and z-axis of the system respectively. What is the work done by this force in moving the body a distance of 4 m along the z-axis ?
A boy is sitting on a chair placed on the floor of a room. Write as many action-reaction pairs of forces as you can.
Is it true that the reaction of a gravitational force is always gravitational, of an electromagnetic force is always electromagnetic and so on?
When Neils Bohr shook hand with Werner Heisenberg, what kind of force they exerted ?
If all matters were made of electrically neutral particles such as neutrons,
(a) there would be no force of friction
(b) there would be no tension in the string
(c) it would not be possible to sit on a chair
(d) the earth could not move around the sun.
Which of the following systems may be adequately described by classical physics ?
(a) motion of a cricket ball
(b) motion of a dust particle
(c) a hydrogen atom
(d) a neutron changing to a proton.
The gravitational force acting on a particle of 1 g due to a similar particle is equal to 6.67 × 10−17 N. Calculate the separation between the particles.
The work done by the external forces on a system equals the change in
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the plane. The motion of the particle takes place in a plane. It follows that
(a) its velocity is constant
(b) its acceleration is constant
(c) its kinetic energy is constant
(d) it moves in a circular path.
A box is pushed through 4.0 m across a floor offering 100 N resistance. How much work is done by the resisting force?
A constant force of 2⋅5 N accelerates a stationary particle of mass 15 g through a displacement of 2⋅5 m. Find the work done and the average power delivered.
A particle moves from a point \[\overrightarrow{r}_1 = \left( 2 m \right) \overrightarrow{ i } + \left( 3 m \right) \overrightarrow{ j } \] to another point
\[\overrightarrow{r}_2 = \left( 3 m \right) \overrightarrow{ i } + \left( 2 m \right) \overrightarrow{ j } \] acts on it. Find the work done by the force on the particle during the displacement.
A force \[F = \alpha + bx\] acts on a particle in the x-direction, where a and b are constants. Find the work done by this force during a displacement from x = 0 to x = d.
Find the average frictional force needed to stop a car weighing 500 kg at a distance of 25 m if the initial speed is 72 km/h.
A 250 g block slides on a rough horizontal table. Find the work done by the frictional force in bringing the block to rest if it is initially moving at a speed of 40 cm/s. If the friction coefficient between the table and the block is 0⋅1, how far does the block move before coming to rest?
In a children's park, there is a slide which has a total length of 10 m and a height of 8⋅0 m . A vertical ladder is provided to reach the top. A boy weighing 200 N climbs up the ladder to the top of the slide and slides down to the ground. The average friction offered by the slide is three tenth of his weight. Find (a) the work done by the ladder on the boy as he goes up; (b) the work done by the slide on the boy as he comes down. Neglect any work done by forces inside the body of the boy
If a force varies linearly with displacement, the area under the F-s graph forms:
The work done by a variable force is calculated using the formula:
What does 'dW' represent in the variable force work calculation?
When force varies non-linearly with displacement, what method must be used to find work?
