2. Physics - Q&A

In a heat pump

• the evaporator loses heat.
• the condenser loses heat.
• the compressor loses heat.

A passive sensor

• does not require power.
• requires dc excitation.
• requires ac power input.

A convex mirror forms a virtual image when

• rarely.
• seldom.
• always.

A force 10 N is placed 2 Meters from a pivot point, what is the moment?

• 20Nm.
• 40Nm.
• 80Nm.

Which of the following statements describes centrifugal force?

• Equal to centripetal force and acts in the opposite direction.
• Greater than centripetal force and acts in the same direction.
• Smaller than centripetal force and acts in the same direction.

What frequency is a tone which is 4 times the fundamental frequency?

• 2nd overtone.
• 3rd overtone.
• 3rd harmonic.

A process where temperature remains the same is known as

• isochoric.
• isobaric.
• isothermic.

What is the angular velocity of a shaft rotating at 300rpm in radians/second?

• 10pi radians/second.
• 2pi radians/second.
• 5pi radians/second.

A lifting machine moves with an effort, a distance of 200 cm, in order to raise it 0.5 m. The Velocity Ratio is

• 8.
• 4.
• 2.

An aircraft of 2 metric tonnes lands with 400 kilojoules of energy, 10 kiloNewtons of force is applied at the brakes, how far does the aircraft take to stop?

• 40 M.
• 80 M.
• 20 M.

How long will it take a car moving at 60 km/hr to travel 90 km?

• 40 minutes.
• 75 minutes.
• 90 minutes.

Two items weighing 11kg and 8kg are placed 2m and 1m respectively aft of the C of G of an aircraft. How far forward of the C of G must a weight of 30kg be placed so as not to change the C of G?

• 2m
• 3m
• 1m

A radar rotates 1 revolution each 30 seconds and uses 10J of energy each revolution. How many joules does it use in a day?

• 28.8 kJ.
• 14.4 kJ.
• 57.6 kJ.

The angular velocity of 500 RPM is, in rads/seconds is equal to

• 33.33pi rads/s.
• 52.36pi rads/s.
• 16.66pi rads/s.

25 litres of fuel exerts a pressure of 10KPa. If a further 125 litres is added, the pressure will now be

• 50 kPa
• 60 kPa
• 40 kPa

Two sound waves of the same frequency and amplitude are moving half a wavelength out of phase with each other. What will be heard?

• Nothing.
• A chord.
• A pulse.

How many electrons does an `S` orbital hold?

• 6.
• 8.
• 2.

A mass of 20kg produces a momentum of 300kgm/s. What is the Kinetic energy?

• 3250 Joules.
• 2250 Joules.
• 4500 Joules.

The oscillation produced by a pendulum 2500mm long has a periodic time of

• 6 seconds.
• 3 seconds.
• 9 seconds.

The work done in lifting a mass of 2000 kg vertically to a height of 40 metres is

• 392.4 kJ.
• 784.8 kJ.
• 196.2 kJ.

An aircraft weighing 6400 pounds lands at a speed of 10 ft/Sec and stops in 10 Seconds. What force was generated by the brakets (asuming gravity as 32 ft/sec).

• -400 Lbs.
• -200 Lbs.
• -640 Lbs.

A fire engine is approaching you with its siren on. As it passes you its pitch

• increases.
• stays the same.
• decreases.

For the CGS system, the force is

• the 'Newton' which produces an acceleration of 1cm/s2 for a mass of gram.
• the 'dyne' which produces an acceleration of 1cm/s2 for a mass of gram.
• the 'pd1' which produces an acceleration of 1 cm/s2 for a mass of gram.

A mass of 10kg placed 2 metres away from a pivot will have a moment of

• 196 NM.
• 150 NM.
• 980 NM.

The tension in the cable of a crane is 2500 N and it lifts a load through 50m, what is the work done on the load?

• 1.25 * 10^5 J
• 2.50 * 10^4 J
• 5.00 * 10^3 J