Which of the following sets of 3 forces CANNOT have a vector sum of zero?

Q-1; Which of the following sets of 3 forces CANNOT have a vector sum of zero?

1) 10, 10 and 10 Newtons
2) 10, 10 and 20 Newtons
3) 10, 20 and 20 Newtons
4) 10, 20 and 40 Newtons
ANSWER: 4 -- 10, 20 AND 40 NEWTONS

Q-1; A small cluster of stars appear, after many decades of observation, to be converging toward a common point in the sky. Does the light from these stars show a:

1) red Doppler shift
2) blue Doppler shift
3) no Doppler shift
ANSWER: 1 -- RED DOPPLER SHIFT

Q-1; What name is given to those elementary particles for which there is a symmetry under intrapair production. Included are photons, pi mesons, and nuclei with an even number of particles.

ANSWER: BOSONS

Q-1;When a fast charged particle traverses a dielectric medium at a velocity exceeding the velocity of light in that medium, radiation is emitted. This radiation is known as:

1) point radiation
2) Cerenkov radiation
3) Synchrotron radiation
4 Bremsstrahlung
ANSWER: 2 -- CERENKOV RADIATION