The potential energy of a particle falling through a straight shaft drilled through the earth (assumed homogenous and spherical) is proportional to____________________?

Select the correct statement_____?

A. The body centrode rolls on the space centrode

B. The space centrode rolls on the body centrode

C. Both body and space centrodes may role on each other

D. The body centrode never touches space centrode

A force P of 50 N and another force Q of unknown magnitude act at 90° to each other. They are balanced by a force of 130 N. The magnitude of Q is__________________?

A. 60 N

B. 80 N

C. 100 N

D. 120 N

If the resultant of two forces has the same magnitude as either of the force, then the angle between the two forces is____________________?

A. 30°

B. 45°

C. 60°

D. 120°

The angles between two forces to make their resultant a minimum and a maximum respectively are__________________?

A. 0° and 90°

B. 180° and 90°

C. 90° and 180°

D. 180° and 0°

The resultant of two forces P and Q is R. If Q is doubled, the new resultant is perpendicular to P. Then_________________?

A. P = R

B. Q = R

C. P = Q

D. None of the above is correct