Advertisements
Advertisements
प्रश्न
A boy pulls a box up to 10 m with a force of 5 kgf. Calculate the work done by him.
Advertisements
उत्तर
Given, force = 5kgf = 5 kgf x 10 ms-2= 50N
displacement = 10m
Work done = force x displacement = 50 x 10 = 500J
APPEARS IN
संबंधित प्रश्न
A body, when acted upon by a force of 10 kgf, moves to a distance 0.5 m in the direction of force. Find the work done by the force. Take 1 kgf = 10 N.
Name the forms of energy which a wound-up watch spring possesses.
A box of weight 150 kgf has gravitational potential energy stored in it equal to 14700 J. Find the height of the box above the ground. (Take g = 9.8 N kg-1)
How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.
Complete the following sentences:
Joule is the unit of .......
Name the physical quantity whose MKS units are kgm2s-3.
A block of mass 30 kg is pulled up a slope, as shown in diagram with a constant speed, by applying a force of 200 N parallel to slope.
A and B are initial and final positions of block.
(i) Calculate the work done by force in moving the block from A to B.
(ii) Calculate P.E. gained by block. [g=10ms-2]
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
Who is the odd one out?
