Waec Physics 1997 Past Questions and Answers

Question 6:

• WAEC 1997

Two forces 3N and 4N act on a body in directions due north and due east respectively. Calculate their equilibrant

A. 5N 53° east of North
B. 5N 53° west of the south
C. 5N 37° north of east
D. 7N 37° west of North
E. 7N 37° south of west

Question 7:

• WAEC 1997

A missile weighing 400N on the earth surface is shot into the atmosphere to an altitude of 6.4 x \(10^{-6}\)m. Taking the earth as a sphere of radius 6.4 x \(10^{-6}\)m and assuming the inverse-square law of universal gravitation, what would be the weight of the missile at that altitude?

A. 100N
B. 200N
C. 400N
D. 800N
E. 1600N

Question 8:

• WAEC 1997

A solid plastic cube of side 0.2m is submerged in a liquid density of 0.8kg\(m^{-3}\). Calculate the upthrust of the liquid on the cube (g=10\(ms^{-2}\)

A. 0.064N
B. 0.025N
C. 0.016N
D. 0.008N
E. 0.003N

Question 9:

• WAEC 1997

A piece of copper of mass 30g loses 60J of heat energy. If the specific heat capacity of copper is 400J\(kg^{-1}K^{-1}\), Calculate the change in the temperature of the copper

A. 0.2K
B. 0.8K
C. 2K
D. 4.5K
E. 5K

Question 10:

• WAEC 1997

Steel bars each of length 3m at 28°C are to be used for constructing a rail line. If the linear expansitivity of the steel is 1 x \(10^{-5}K^{-1}\),what is the safety gap that must be left between the successive bars if the highest temperature expected is 40°C?

A. 1.2x \(10^{-1}cm\)
B. 7.2x\(10^{-1}cm\)
C. 6x\(10^{-1}cm\)
D. 3.6x\(10^{-1}cm\)
E. 1.8x\(10^{-1}cm\)