A direct current of 5A flow through a 0.2H inductor. Calculate the energy stored in the inductor

• A. 0.5J
• B. 1.0J
• C. 2.5J
• D. 5.0J

(a) Explain the term work

(b) Draw a diagram of a pulley system with a velocity ratio of 5.

(c) A man pulls up a box of mass 70kg using an inclined plane of effective length 5m onto a platform 2.5m high at uniform speed. If the frictional force between the box and the plane is 100N, draw the diagram of all the forces acting on the box when in motion and calculate the

(i) minimum effort applied in pulling up the box

(ii) velocity ratio of the plane

(iii) mechanical advantage of the plane

(iv) efficiency of the plane

(v) energy lost in the system

(vi) work output of the man

(vii) total power developed by the man given that the time taken to raise the box onto the platform is 50s. (g = 10ms\(^{-2}\)).

An object is weighted at different locations on the earth. What will be the right observation?

• A) Both the mass and weight are constant
• B) Both the mass and weight vary
• C) the mass is constant while the weight varies
• D) the weight is constant while the mass varies

The momentum of a car moving at a constant speed in a circular track

• A. can be both positive and negative
• B. can be zero depending on its position in the track
• C. can be zero depending on its position in the track
• D. a centrifugal

A man weight 800N climbs up a stairs to height of 15m in 12.5s. What is the man''s average power output?

• A. 667W
• B. 810W
• C. 960W
• D. 15000W

Lamps in domestic lightings are usually in

• A. series
• B. divergent
• C. convergent
• D. parallel

The diagram below illustrates a bar magnet near a coil connected to a galvanometer, When the magnet is rapidly moves towards the coil i. e.m.f. is induced in the coil ii. the galvanometer needle deflects iii. the magnet is attracted by the coil. Which of the statements above is/are correct?

• A. i only
• B. ii only
• C. iii only
• D. i and iii only

The pair of physical quantities that are scalar only are ?

• A. volume and area
• B. moment and momentum
• C. length and displacement
• D. Impulse and time

the property that is propagated in a traveling wave is

• A. frequency
• B. amplitude
• C. energy
• D. wave lenght

At what frequency would a 10H inductor have a reactance of 2000Ω?

• A. π/200Hz
• B. π/100Hz
• C. 100/πHz
• D. 100πHz