441. An electric motor is required to haul a cage of mass 400 kg up a mineshaft through a vertical height of 1200 m in 2 minutes. If the overall efficiency is 80%, how much electricity will be required?
A. 3.2 kW
B. 5.1 kW
C. 32 kW
D. 50 kW
442. A 2 kg body and a 3 kg body have equal momentum. If the kinetic energy of the 3 kg body is 10 J, the KE of the 2 kg body will be:
A. 6.66 J
B. 15.0 J
C. 22.5 J
D. 45.0 J
443. A car of mass m has an engine, which can deliver power p. How much time must pass before the vehicle can accelerate from rest to speed v?
A. mv/p
B. P/mv
C. mv²/2P
D. 2p/mv²
444. Angle subtended at the center of the circle by a body is called:
A. Angular velocity
B. Linear velocity
C. Angular displacement
D. Linear displacement
445. When a body moves in a circle in the clockwise direction, the angular displacement θ is taken as:
A. Positive
B. Negative
C. Neutral
D. Absolute
446. The torque on a body will be zero if the angle between r and F is:
A. 90 Degree
B. 180 Degree
C. 270 Degree
D. 45 Degree
447. The direction of angular displacement is determined by using:
A. Heat to tail rule
B. Fleming left-hand rule
C. Right-angle rule
D. None of these
448. Which part of a transistor is doped the heaviest to supply charge carriers?
A) Emitter
(B) Base
(C) Collector
(D) All of the above
449. The value of the coefficient of linear thermal expansion of brass is?
A) 1.9×10⁻⁵K⁻¹
(B) 1.9×10⁻⁶K⁻¹
(C) 1.9×10⁻⁷K⁻¹
(D) 1.9×10⁻⁸K⁻¹
450. Specific heat of ice is?
(A) 2200 Jkg⁻¹K⁻¹
(B) 2400 Jkg⁻¹K⁻¹
C) 2100 Jkg⁻¹K⁻¹
(D) 2300 Jkg⁻¹K⁻¹
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