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
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 lawyer alleges in court that the police had forced his client to issue a statement of confession. What kind of force is this ?
When you hold a pen and write on your notebook, what kind of force is exerted by you on the pen? By the pen on the notebook? By you on the notebook?
Suppose the magnitude of Nuclear force between two protons varies with the distance between them as shown in figure. Estimate the ratio "Nuclear force/Coulomb force" for
(a) x = 8 fm
(b) x = 4 fm
(c) x = 2 fm
(d) x = 1 fm (1 fm = 10 −15m).
When Neils Bohr shook hand with Werner Heisenberg, what kind of force they exerted ?
Calculate the force with which you attract the earth.
A body builder exerts a force of 150 N against a bullworker and compresses it by 20 cm. Calculate the spring constant of the spring in the bullworker.
Two charged particles placed at a separation of 20 cm exert 20 N of Coulomb force on each other. What will be the force of the separation is increased to 25 cm?
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?
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?
The 200 m free-style women's swimming gold medal at Seoul Olympics in 1988 was won by Heike Friendrich of East Germany when she set a new Olympic record of 1 minute and 57⋅56 seconds. Assume that she covered most of the distance with a uniform speed and had to exert 460 W to maintain her speed. Calculate the average force of resistance offered by the water during the swim.
A uniform chain of length L and mass M overhangs a horizontal table with its two third part on the table. The friction coefficient between the table and the chain is μ . Find the work done by friction during the period the chain slips off 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 lawn roller is pulled along a horizontal surface through a distance of 20 m by a rope with a force of 200 N. If the rope makes an angle of 60° with the vertical while pulling, the amount of work done by the pulling force is:
A body is being raised to a height h from the surface of earth. What is the sign of work done by gravitational force?
A graph of potential energy V(x) verses x is shown in figure. A particle of energy E0 is executing motion in it. Draw graph of velocity and kinetic energy versus x for one complete cycle AFA.
If a force varies linearly with displacement, the area under the F-s graph forms:
What does 'dW' represent in the variable force work calculation?
