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JAMB Physics Past Questions & Answers - Page 151

751.

A particle of weight 120N is placed on a plane inclined at 300 to the horizontal. If the plane has an efficiency of 60% to the floor what is the force required to push the weight uniformly up the plane?

A.

50N

B.

100N

C.

175N

D.

210N

Correct answer is B

Efficiency = W(120N)INPUTWORKOUTPUT×1001

And for incline plane

V.R =1Sinθ=V.R=1Sin30=10.5=2therefore 60120=M.A2=M.A=120100=1.2but M.A =loadeffort=120Etherefore120E=1.2=E=1201.2=100N


Therefore Effort up the plane = 100N

752.

An alternating current with a frequency of 100HZ has a period of

A.

0.03sec

B.

0.01sec

C.

0.04sec

D.

0.15sec

Correct answer is B

F = 100HZ, period, T = 1/f = 1/100

= 0.01 sec

The period (T) = 0.01sec

753.

Momentum and Kinetic energy are conserved in

A.

Inelastic collision

B.

Elastic collision

C.

Explosion

D.

Spacecraft

Correct answer is B

Momentum and kinetic energy are conversed in elastic collision

754.

The property of a body to remain at rest or to continue to move in a straight line is known as

A.

force

B.

Impulse

C.

Energy

D.

Inertia

Correct answer is D

Inertia: the property of a body that resists any change to its uniform motion, equivalent to its mass

755.

The normal temperature of human body is record at what ranges?

A.

27°C to 43°C

B.

30°C to 40°

C.

98.4°C only

D.

Between 35°C to 37°C

Correct answer is D

The range of temperature is between 35°C and 43°C but for normal temperature of human body is between the range of 35°C to 37°C respectively