Unformatted text preview: 77777 'I . 7. A uranium nucleus (mass 238 units) at rest decays into a helium nucleus (mass 4.0 units) and a thorium nucleus (mass
234 units). If the speed of the helium nucleus is 6.0 x 105m/s, what is the speed of the thorium nucleus? @10 x 104m/s (2) 3.0 x 104m/s (3) 3.6 x 104m/s (4) 4.1 x 104m/s (5) Not enough information 8. An eggdropped on the road usually breaks, while one dropped on the grass usually doesn’t break. This is because for the
egg dropped on the grass: 1 the time interval for stopping is greater
the change in momentum is less. the egg weighs less in the grass. the time interval for stopping is less.
the change in momentum is greater. CHAD-7 VStarting from rest, a. wheel undergoes constant angular acceleration for a period of time T. At which of the following
times does the average angular acceleration equal the instantaneous angular acceleration? (1) They are equal at all times. (2) at 0.67 T only (3) at 0.71 T only (4) at 0.25 T only (5) at 0.50 T only 10. A 1 500-kg car rounds an unbanked curve with a radius of 52 m at a speed of 12 m/s. What minimum road/ tire coefﬁcient
of friction must exist to prevent the car from slipping? @028 (2) 0.30 (3) 0.18 (4) 0.37 (5) 0.03 11. %onsider a frictionless track (see ﬁgure). A block of mass ® ﬁns.
;m1 = 4.40 kg is released from point A (5 In higher than I point B . Block m1 collides head-on with block m2 that / is initi y at rest (mass m; = 11.5 kg) . Calculate the 5.00m.)
maximum height to which m1 rises after the collision. * The collissiion is elastic. , l, _ ﬂ _ ,5; .. __ ...l
[9 © (1) 0.997 m (2) 5.00 m (3) 2.61 m (4) 0.383 m (5) 5.00 m 12. Calculate the angular speed about the rotational axis of the Earth of a person standing on the surface? @125 x 10‘5rad/s (2) 3.6 x 10‘5rad/s (3) 6.2 x 10'5rad/s (4) 3.1 x 10‘5rad/s (5) cannot determine without knowing
la itude of person 13. A ceiling fan is turned on and reaches an angular speed of 120 rev/min in 20 s. It is then turned off and coasts to a stop in an additional 40 s. The ratio of the average angular acceleration for the ﬁrst 20 s to that for the last 40 s is which of
the following? @—2 (2) 0.5 (3) —0.5 (4)2 (5) 1 14. Consider a point on a bicycle wheel as the wheel turns about a ﬁxed axis, neither speeding up nor slowing down. Which
one of the following statements is true: (a The angular velocity is constant. ’4 None of the other statements are true.
. The linear velocity is constant. g Neither angular nor linear velocity is constant.
. Both angular and linear velocities are constant. 58 ...
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- Spring '06