Question 561:

• JAMB 1989

The function of a 5-A fuse included in a circuit supplying a household refrigerator with power is to keep the

A. Temperature of the refrigerator low and constant
B. Keep current supplied to the refrigerator below 5A
C. Voltage supply constant
D. Current supplies to the refrigeration

Question 562:

• JAMB 1989

The fig above shows a uniform circular object, center R and diameter PS. A circular section 6 and Diameter PR is cut from it. if PQRS is a straight line, where is center of gravity of the figure

A. Q
B. R
C. A point between P and R
D. A point between R and S

Question 563:

• JAMB 1989

A simple pendulum of mass m moves along an arc pf a circle radius R in a vertical plane as shown above. What is the work done by gravity in a downward swing through the angle q to 0 degree

A. MgR sinθ
B. MgR (1- cos θ)
C. MgR
D. MgR (1 - sinθ)

Question 564:

• JAMB 1989

A block of mass m is held in equilibrium against a vertical wall by a horizontal force. If the coefficient of friction between the wall and the block is µ, the minimum value of the horizontal force is

A. µmg
B. (1-µ)mg
C. (1+µ)mg
D. Mg/µ

Question 565:

• JAMB 1989

In the fig above W1 = 200g, and W2 =450g . Calculate the extension of the spring per unit load?
[g = 10ms^-2]

A. 6.0 x 10^-5mN^-1
B. 2.5 x 10^-4mN^-1
C. 6.0 x 10 ^-3mN^-1
D. 2.5 x 10 ^-2mN^-1