Advertisements
Advertisements
प्रश्न
A block of mass 2 kg kept at rest on an inclined plane of inclination 37° is pulled up the plane by applying a constant force of 20 N parallel to the incline. The force acts for one second. Show that the work done by the applied force does not exceed 40 J.
Advertisements
उत्तर
Given:
\[\text{ Mass of the block, m = 2 kg } \]
\[\theta = 37^\circ\]
\[\text{ Force on the block, F = 20 N } \]
From the above figure,
\[F = \left( 2g \sin \theta \right) + ma\]
\[ \Rightarrow a = \frac{20 - 20 \sin \theta}{2} = 4 \text{ m/ s}^2 \]
\[s = ut + \frac{1}{2}a t^2 = 2 m\]
\[\text{ So, work done } \]
\[W = FS = 20 \times 2 = 40 J\]
APPEARS IN
संबंधित प्रश्न
State if the following statement is true or false. Give a reason for your answer.
Work done in the motion of a body over a closed loop is zero for every force in nature.
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.
A lawyer alleges in court that the police had forced his client to issue a statement of confession. What kind of force is this ?
A neutron exerts a force on a proton which is
(a) gravitational
(b) electromagnetic
(c) nuclear
(d) weak
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.
Two spherical bodies, each of mass 50 kg, are placed at a separation of 20 cm. Equal charges are placed on the bodies and it is found that the force of Coulomb repulsion equals the gravitational attraction in magnitude. Find the magnitude of the charge placed on either body.
The magnetic force on a charged particle is always perpendicular to its velocity. Can the magnetic force change the velocity of the particles? Speed of the particle?
The work done by the external forces on a system equals the change in
The work done by all the forces (external and internal) on a system equals the change in ______.
A block of mass m slides down a smooth vertical circular track. During the motion, the block is in
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.
Find the average force needed to accelerate a car weighing 500 kg from rest to 72 km/h through a distance of 25 m.
A uniform chain of mass m and length l overhangs a table with its two third part on the table. Find the work to be done by a person to put the hanging part back on the table.
A particle of mass m is kept on a fixed, smooth sphere of radius R at a position where the radius through the particle makes an angle of 30° with the vertical. The particle is released from this position. (a) What is the force exerted by the sphere on the particle just after the release? (b) Find the distance travelled by the particle before it loses contact with the sphere.
A force F = 20 + 10y acts on a particle in y-direction where F is in newton and y in metre. Work done by this force to move the particle from y – 0 to y – 1 m is:
A body is being raised to a height h from the surface of earth. What is the sign of work done by applied force?
A block of mass m is taken from A to B slowly under the action of a constant force R Work done by this force is ______.
Force acting on a particle is (2`hat"i"` + 3 `hat"j"`) N. Work done by this force is zero, when a particle is moved on the line 3y + kx = 5. Here value of k is ______.
