5. The acceleration of an object travelling with "uniform circular motion," is a. directed toward the centre of the circle b. directed tangent to the circle C. zero because the speed is constant d. changing in magnitude depending on its position in the circle e . directed outward from the centre of the circle 6. Astronauts on board an orbiting space station appear to be "floating" because . they are in the vacuum of space b. they are outside Earth's gravitational influence C. they are in free fall along with the space station itself d. they have become truly "weightless" e. they are pulled by the gravity of the moon 7. The recoil velocity of an unconstrained rifle of mass 5.0 kg after it shoots a 52 g bullet at a speed of 3.0 x 10 m/s [ W] is a. 0.87 m/s [E] c. 29 m/'s [E] b. 3.1 m/s [E] d. 31 m/s [E] 8. Two objects, P and Q, have the same momentum. Q can have more kinetic energy than P if it has: a. More mass than P . The same mass as P More speed than P . The same speed as P 9. Earth's mass is 5.98 x 1024 kg. Calculate the value of g at a point 7.2 x 10" km from the centre of Earth. a. 9.8 x 10 N/kg d. 1.7 x 10' N/kg b. 7.6 x 10' N/kg c. 5.8 x 10' N/kg c. 1.7 x 10 'N/kg 10. A piece of paper becomes electrically charged when a charged rod of plastic is placed close to it. This is referred to as a. charging by a conductor d. charging by contact b. charging by electricity c. charging by induction c. charging by an insulator 1 1. The electrostatic force between two point charges is 5.7x10 N. If the distance between the charges is tripled while the charge on one of them triples and the charge on the other doubles, the force between them will be a. 1.3 x10 N d. 2.6x10 N b. 3.1 x10 N C. 3.8 x 10 N C. 8.6x 10' N 12. In a two-point source interference pattern in a ripple tank, a point is one wavelength farther from one source than the other. If the two sources are in phase, then there is a. constructive interference at this point b. destructive interference at this point C. both constructive and destructive interference simultaneously d. neither constructive nor destructive interference at this point e. no interaction between the two waves at this point