What are the correct answers for these multiple choice questions?

1. An object is moving on a circular path with constant speed. Which of the following statements is correct?

A.

The net force on the object cannot be zero, since the direction of the motion cannot change without a net force.

B.

The net force on the object must be zero, since its speed is constant.

C.

We cannot determine the net force on the object, as we don't know all the forces involved.

D.

The net force sometimes is zero and sometimes not, depending on the location of the object.

E.

None of the above

2. When you shake a water bottle, you would feel its:

A.

Weight

B.

Mass

C.

Height

D.

Both its weight and mass

E.

Quality

3. The astronauts in International Space Station are in an afloat state. Why?

A.

Because of their distance from Earth, the gravitational force of the earth on them is very small.

B.

Because their distance from Earth, the gravitational force of the earth on them is precisely zero.

C.

They are afloat because they are constantly in free fall and will eventually crash to earth.

D.

They are afloat because they are constantly in free fall and because of their tangential velocity they move in an orbit.

E.

They are afloat because they are bunch of show-offs and have nothing better to do up there.

4. If you move from Earth to Mars:

A.

both your mass and weight will change.

B.

your mass will change but your weight will stay the same.

C.

your weight will change but your mass will stay the same.

D.

neither your mass nor your weight will change.

E.

not enough information is provided.

5. In mid-19th century, James Maxwell's theory of electromagnetism predicted that the speed of light is constant and does not depend on the speed of the source or the observer. What experiment proved the constancy of speed of light? and what physical phenomenon was this experiment based on?

A.

Michaelson-Morley experiment which was based on diffraction of waves

B.

Fizzeau's experiment which was based on diffraction of waves

C.

Michaelson-Morley experiment which was based on interference of waves

D.

Fizzeau's experiment which was based on the interference of the waves.

E.

Tom's experiment on Jerry, based on cat-mouse duality.

6. Since some old physicists found it painful to accept the constancy of speed of light and the fact that it travels in vacuum, they came up with the idea of Aether. Which experiment disproved this hypothesis and what physical principal was it based on?

A.

Michaelson-Morley experiment which was based on diffraction of waves

B.

Fizzeau's experiment which was based on diffraction of waves

C.

Michaelson-Morley experiment which was based on interference of waves

D.

Fizzeau's experiment which was based on the interference of the waves.

E.

Jerry's experiment on Tom, based on cat-mouse duality.

7. Is it correct to claim that according to Special Relativity, everyone's clock in the universe is different than everyone else's?

A.

Yes, because according to Einstein's SR, time is relative and runs differently for everyone.

B.

Yes, because time is an internalized sense in people and is different from a person to person.

C.

No, because according to SR, time is absolute.

D.

No, because according to SR, time is only relative when there is relative motion.

E.

None of the above

8. You are assigned to measure the speed of a beam of light coming from a distant galaxy. The said galaxy is moving away from you with 0.9 c, where c is the speed of light. What is the speed that you're going to measure for the beam of light?

A.

Obviously, 0.9 c

B.

Obviously, 1.8 c

C.

Obviously, c

D.

Obviously, 1.1 c

E.

Obviously, you're joking Hossein! No galaxy with such a mass could move with 0.9 c

9. You are on board a Fast Warp Drive (FWD) that can move with speeds up to 0.95 c. The enemy from another galaxy is approaching you from the opposite direction on their Slow Worm Ship (SWS) with a speed of 0.8 c. SWS shoots a laser beam towards your ship. Your detector receives the beam and measures its speed to be:

A.

0.95 c

B.

1.75 c

C.

0.8 c

D.

0.15 c

E.

c

10. In the previous question what would you measure for the speed of SWS?

A.

0.95 c+ 0.8 c = 1.75 c

B.

c

C.

a speed higher than 0.8 c but less than c.

D.

1.1 c

E.

0.8 c