JAMB Physics Past Questions & Answers - Page 309

1,542.

A cone in an unstable equilibrium has its potential energy

A.

decreased

B.

increased

C.

unchanged

D.

oscillating

Correct answer is B

No explanation has been provided for this answer.

1,543.

An object of mass 50kg is released from a height of 2m.Find the kinetic energy just before it strikes the ground

A.

250J

B.

1000J

C.

10 000J

D.

100 000J

Correct answer is B

P.E = K.E = mgh

= 50 x 10 x 2 = 1000J

1,544.

Which of the following is TRUE of a particle moving in a horizontal circle with constant angular velocity?

A.

The energy is costant but the linear momentum varies

B.

The linear momentum is conatant but the energy varies

C.

both energy and linear momentum are constant

D.

The speed and the linear velocity are both constant

Correct answer is C

No explanation has been provided for this answer.

1,545.

A motor vehicle is brought to rest from a speed of 15ms-1 in 20 seconds. Calculate the retardation.

A.

0.75ms-1

B.

1.33ms-2

C.

5.00ms-2

D.

7.50ms-2

Correct answer is A

Retardation = \(\frac{u - v}{t}\)

= \(\frac{15 -0}{20}\)

= 0.75ms-1