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On tripling the speed of motion of a body, the change in K.E. is:
The moon revolves around the earth due to the gravitational force (F) of the earth on the moon. The work done by the gravitational force is (r = radius of the circular orbit of moon):
An electric bulb of 60 W is used for 5 hours a day. The cost of electricity involved in a month of 30 days at Rs. 3.00 per unit is (in Rs):
A body is moved through a distance of 3 m in the following different ways. In which case is the maximum work done?
A: 50 kg man climbing a ‘slant length of 5 m along a 30° incline.
B: 25 kg man running with 2 m/s speed.
C: A force of 5 N acting on an object moving with 5 m/s speed for 5 min.
If the energies in A, B and C are E_{A}, E_{B} and E_{C} respectively, then:
Two bodies of equal weight are kept at heights of h and 1.5 h, respectively. The ratio of their potential energies is:
If a force of F newton moves a body with constant speed v, the power delivered by it is:
A mass ‘m’ falls from a height ‘h’ any point on its path the total energy is:
If the bulbs of 60 W and 40 W are connected in series to a 220 V source the bulb which glows brighter is:
A porter with a suitcase on his head is climbing up a flight of stairs with a uniform speed. The work done by the ‘weight of the suitcase’ on the suitcase is:
Two bodies of unequal masses are dropped from a cliff. At any instant, they have equal:
Two masses m and 2m are dropped from a certain height ‘h’. Then on reaching the ground:
A person A does 500 J of work in 10 minutes and another person B does 600 J of work in 20 minutes. Let the power delivered by A and B be P_{A} and P_{B} respectively. Then,
In the case of negative work, the angle between the force and displacement is:
One unit of electricity is consumed by,
A: P = 40 W bulb used for t = 25 hours
B: P = 20 W bulb used for t = 50 hours
Both A and B are true as, energy E in kWh is best related as:
The work done on an object does not depend upon the______.
165 videos449 docs327 tests

165 videos449 docs327 tests
