Advertisements
Advertisements
Question
A box is pushed through 4.0 m across a floor offering 100 N resistance. How much work is done by the resisting force?
Advertisements
Solution
Resisting force acting on the box, \[F = 100 N\]
Displacement of the box, S = 4 m
Also,
\[\theta = 180^\circ\]
∴ Work done by the resisting force,
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 body of mass m is placed on a table. The earth is pulling the body with a force mg. Taking this force to be the action what is the reaction?
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 ?
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).
Figure shows a cart. Complete the table shown below.
| Force on | Force by | Nature of the Force | Direction |
| Cart |
1 |
||
| Horse |
1 |
||
| Driver |
1 |
Let E, G and N represent the magnitudes of electromagnetic gravitational and nuclear forces between two electrons at a given separation. Then
A neutron exerts a force on a proton which is
(a) gravitational
(b) electromagnetic
(c) nuclear
(d) weak
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 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.
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. Find the work done by the force of gravity in that one second if the work done by the applied force is 40 J.
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?
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 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 moving unidirectionally under the influence of a source of constant power supplying energy. Which of the diagrams shown in figure correctly shows the displacement-time curve for its motion?
A body is being raised to a height h from the surface of earth. What is the sign of work done by gravitational force?
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 ______.
In the integration method for variable force, why do we divide displacement into tiny segments (ds)?
