Workdone on an object to bring it to a certain point in space is called
Gravitational potential energy
Potential energy
Kinetic energy
Mechanical energy
Correct answer is A
Gravitational potential energy is the energy an object possesses because of its position in a gravitational field. Since the force required to lift it is equal to its weight, it follows that the gravitational potential energy is equal to its weight times the height to which it is lifted. (i.e, P.E\(_g\) = ωh, where ω = mg)
1.05 × 10\(^{-2}\)ms\(^{-1}\)
1.85 × 10\(^{-4}\)ms\(^{-1}\)
9.50 × 10\(^{-1}\)ms\(^{-1}\)
5.25 × 10\(^{-3}\)ms\(^{-1}\)
Correct answer is A
Length of the seconds hand = r = 0.1m but the seconds hand rotates through 360° or 2π rad in 60s.
| Thus, | ω | = | θ | = | 2π
60 |
Velocity of the tip of the hand, V = ωr
| V | = | 2π
60 |
× | 0.1 | = | 2π
600 |
= | π
300 |
= | 3.142
300 |
V = 0.01047 = 1.05 × 10\(^{-2}\)ms\(^{-1}\)
1800J
1600J
600J
440J
Correct answer is B
Potential energy at the highest point = mgh
PE = 4 × 10 × 40 = 1600J
The part of the human eye that does similar work as the diaphragm of a camera lens is the
Ciliary muscles
Pupil
Iris
Retina
Correct answer is C
Iris is similar to diaphragm.
Conduction only
Convection only
Radiation only
All these methods
Correct answer is C
Vacuum is an enclosure with no air or agent of heat transfer